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 A325972 a(n) is the largest k <= sigma(n)-A007947(n) such that n-k and n-(sigma(n)-k) are relatively prime. 4
 0, 1, 0, 5, 0, 5, 0, 13, 10, 7, 0, 21, 0, 9, 8, 29, 0, 32, 0, 31, 10, 13, 0, 53, 26, 15, 36, 29, 0, 41, 0, 61, 14, 19, 12, 85, 0, 21, 16, 79, 0, 53, 0, 61, 62, 25, 0, 117, 50, 83, 20, 71, 0, 113, 16, 105, 22, 31, 0, 137, 0, 33, 82, 125, 18, 77, 0, 91, 26, 73, 0, 188, 0, 39, 108, 101, 18, 89, 0, 175, 118, 43, 0, 181, 22 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Antti Karttunen, Table of n, a(n) for n = 1..20000 Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537 FORMULA a(n) = A000203(n) - A325971(n). PROG (PARI) A007947(n) = factorback(factorint(n)[, 1]); \\ From A007947 A325972(n) = { my(s=sigma(n)); forstep(i=s-A007947(n), 0, -1, if(1==gcd(n-i, n-(s-i)), return(i))); }; CROSSREFS Cf. A000203, A007947, A324213, A325818, A325962, A325966, A325970, A325971. Sequence in context: A071873 A036478 A059628 * A073441 A202325 A337084 Adjacent sequences: A325969 A325970 A325971 * A325973 A325974 A325975 KEYWORD nonn AUTHOR Antti Karttunen, May 31 2019 STATUS approved

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Last modified March 22 04:35 EDT 2023. Contains 361413 sequences. (Running on oeis4.)