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 A341530 a(n) = gcd(n*sigma(A003961(n)), sigma(n)*A003961(n)), where A003961 shifts the prime factorization of n one step towards larger primes, and sigma is the sum of divisors of n. 13
 1, 1, 2, 1, 2, 36, 4, 5, 1, 2, 2, 36, 2, 24, 120, 1, 2, 9, 4, 2, 8, 4, 6, 180, 1, 18, 4, 168, 2, 360, 2, 7, 12, 2, 336, 117, 2, 12, 4, 10, 2, 288, 4, 364, 30, 24, 6, 36, 19, 3, 360, 18, 6, 72, 56, 120, 16, 2, 2, 360, 2, 16, 4, 1, 12, 144, 4, 2, 60, 336, 2, 45, 2, 6, 10, 12, 264, 72, 4, 2, 11, 2, 6, 2016, 4, 12, 24 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Antti Karttunen, Table of n, a(n) for n = 1..8191 Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537 Index entries for sequences computed from indices in prime factorization Index entries for sequences related to sigma(n) FORMULA a(n) = gcd(A341528(n), A341529(n)) = gcd(n*A003973(n), A000203(n)*A003961(n)). a(n) = gcd(A341512(n), A341528(n)) = gcd(A341512(n), A341529(n)) = A342670(A003961(n)). - Antti Karttunen, Mar 24 2021 PROG (PARI) A003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961 A341530(n) = { my(t=A003961(n), s=sigma(t)); gcd((n*s), sigma(n)*t); }; CROSSREFS Cf. A000203, A003961, A003973, A028982 (positions of odd terms), A341512, A341526, A341527, A341528, A341529, A342670. Cf. A342674 (same sequence applied onto prime shift array A246278). Sequence in context: A136156 A191657 A155796 * A141238 A094690 A010249 Adjacent sequences: A341527 A341528 A341529 * A341531 A341532 A341533 KEYWORD nonn AUTHOR Antti Karttunen, Feb 16 2021 STATUS approved

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Last modified November 29 05:28 EST 2023. Contains 367422 sequences. (Running on oeis4.)