Výsledky vyhledávání - "Charles R. Wall"

Autor: Charles R. Wall

Publikováno v: Canadian Mathematical Bulletin. 18:115-122

A divisor d of a positive integer n is a unitary divisor if d and n/d are relatively prime. An integer is said to be unitary perfect if it equals the sum of its proper unitary divisors. Subbarao and Warren [2] gave the first four unitary perfect numb

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::474c18677d2b24381da476176f5bc6b7
https://doi.org/10.4153/cmb-1975-021-9

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Bi-unitary perfect numbers

Autor: Charles R. Wall

Publikováno v: Proceedings of the American Mathematical Society. 33:39-42

Let d be a divisor of a positive integer n. Then d is a unitary divisor if d and nld are relatively prime, and d is a bi-unitary divisor if the greatest common unitary divisor of d and nld is 1. An integer is bi-unitaty perfect if it equals the sum o

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::1461f74b2d728d76c68fd905e8055d8f
https://doi.org/10.1090/s0002-9939-1972-0289403-9

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Density bounds for the sum of divisors function

Autor: Charles R. Wall, Phillip L. Crews, Donald B. Johnson

Publikováno v: Mathematics of Computation. 26:773-777

Upper and lower bounds are presented for the density of the integers n n for which σ ( n ) / n ≧ x \sigma (n)/n \geqq x , where σ ( n ) \sigma (n) is the sum of divisors of n n , and 1 ≦ x ≦ 5 1 \leqq x \leqq 5 .

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::54484379684516e793823ef854ed00bd
https://doi.org/10.1090/s0025-5718-1972-0327700-7

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Density bounds for Euler’s function

Autor: Charles R. Wall

Publikováno v: Mathematics of Computation. 26:779-783

Let φ \varphi be Euler’s function. Upper and lower bounds are presented for D ( x ) D(x) , the density of the integers n n for which φ ( n ) / n ≦ x \varphi (n)/n \leqq x . The bounds, for x = 0 ( .01 ) 1 x = 0(.01)1 , have an average spread of

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::db6834cef5fe15fae61896ad676c2e6e
https://doi.org/10.1090/s0025-5718-1972-0327701-9

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Density bounds for the sum of divisors function

Autor: Phillip L. Crews, Donald B. Johnson, Charles R. Wall

Publikováno v: Lecture Notes in Mathematics ISBN: 9783540057239

Upper and lower bounds are presented for the density of the integers n for which ac(n)/n ' x, where a(n) is the sum of divisors of n, and 1 _ x _ 5.

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::6b261becd064cfe1604641f831b27044
https://doi.org/10.1007/bfb0058798

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