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 A259694 a(n) = Sum(k^6*sigma(k)*sigma(n-k),k=1..n-1). 1
 0, 1, 195, 3496, 38195, 192780, 977386, 3216320, 9860049, 27321870, 65803045, 144005856, 308944925, 635774072, 1112550390, 2153146880, 3618341556, 6391671525, 9949570455, 16725562160, 24691972080, 40979569092, 56807498030, 89450231040, 120404165825 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS This was formerly A001479. LINKS Colin Barker, Table of n, a(n) for n = 1..1000 J. Touchard, On prime numbers and perfect numbers, Scripta Math., 129 (1953), 35-39. [Annotated scanned copy] MAPLE S:=(n, e)->add(k^e*sigma(k)*sigma(n-k), k=1..n-1); f:=e->[seq(S(n, e), n=1..30)]; f(6); PROG (PARI) a(n) = sum(k=1, n-1, k^6*sigma(k)*sigma(n-k)) \\ Colin Barker, Jul 16 2015 CROSSREFS Sequence in context: A172354 A295130 A257765 * A066232 A284960 A226105 Adjacent sequences:  A259691 A259692 A259693 * A259695 A259696 A259697 KEYWORD nonn AUTHOR N. J. A. Sloane, Jul 03 2015 STATUS approved

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Last modified December 6 19:15 EST 2021. Contains 349567 sequences. (Running on oeis4.)