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 A318505 Sum of divisors of n, up to, but not including the second largest of them A032742(n); a(1) = 0 by convention. 9
 0, 0, 0, 1, 0, 3, 0, 3, 1, 3, 0, 10, 0, 3, 4, 7, 0, 12, 0, 12, 4, 3, 0, 24, 1, 3, 4, 14, 0, 27, 0, 15, 4, 3, 6, 37, 0, 3, 4, 30, 0, 33, 0, 18, 18, 3, 0, 52, 1, 18, 4, 20, 0, 39, 6, 36, 4, 3, 0, 78, 0, 3, 20, 31, 6, 45, 0, 24, 4, 39, 0, 87, 0, 3, 24, 26, 8, 51, 0, 66, 13, 3, 0, 98, 6, 3, 4, 48, 0, 99, 8, 30, 4, 3, 6, 108, 0, 24, 24, 67, 0, 63, 0, 54, 52 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 FORMULA a(1) = 0; for n > 1, a(n) = A001065(n)-A032742(n). PROG (PARI) A001065(n) = (sigma(n)-n); A032742(n) = if(1==n, n, n/vecmin(factor(n)[, 1])); A318505(n) = if(1==n, 0, A001065(n)-A032742(n)); A318505(n) = sumdiv(n, d, (d

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Last modified June 6 11:14 EDT 2020. Contains 334827 sequences. (Running on oeis4.)