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 A115071 Numerator of 1^n/n + 2^n/(n-1) + 3^n/(n-2) +...+ (n-1)^n/2 + n^n/1. 5
 1, 9, 94, 3625, 18631, 1120581, 34793764, 5692787001, 29669041771, 30708223774261, 134127439064434, 302304605103335861, 2387352152511746837, 109134149200789179825, 24217460586461892638584 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(p-1) is divisible by p^3 for prime p>3. a(p^2-1) is divisible by p^6 for prime p>3. a(p^3-1) is divisible by p^9 for prime p>3. LINKS FORMULA a(n) = numerator[ Sum[ i^n/(n+1-i), {i,1,n}]. EXAMPLE a(1) = numerator[1/1] = 1 a(2) = numerator[1/2 + 4/1] = 9 a(3) = numerator[1/3 + 4/2 + 9/1] = 94 a(4) = numerator[1/4 + 4/3 + 9/2 + 16/1] = 3625 MATHEMATICA Table[Numerator[Sum[i^n/(n+1-i), {i, 1, n}]], {n, 1, 20}] CROSSREFS Cf. A001008, A027612. Sequence in context: A307961 A099297 A057782 * A000562 A193216 A213019 Adjacent sequences:  A115068 A115069 A115070 * A115072 A115073 A115074 KEYWORD frac,nonn AUTHOR Alexander Adamchuk, Jun 17 2006 STATUS approved

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Last modified September 27 15:18 EDT 2021. Contains 347691 sequences. (Running on oeis4.)