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A087301 a(n) = n!*Sum_{i=1..n-1} (-1)^(i+1)/i. 1
2, 3, 20, 70, 564, 3108, 30624, 230256, 2705760, 25771680, 352805760, 4067556480, 63651813120, 861371884800, 15176802816000, 235775183616000, 4620563523072000, 81032645804544000, 1748700390205440000 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,1
COMMENTS
Stirling transform of A052882(n)=[0,2,9,52,375,...] is a(n+1)=[0,2,3,20,...]. - Michael Somos, Mar 04 2004
LINKS
FORMULA
E.g.f.: x*log(1+x)/(1-x). a(n) = 1/2*(-1)^n*n!*(2*(-1)^n*log(2)+Psi(1/2+1/2*n)-Psi(1/2*n)).
a(n) ~ n! * log(2). - Vaclav Kotesovec, Jul 01 2018
MATHEMATICA
Rest[Table[n!Sum[(-1)^(i+1)/i, {i, n-1}], {n, 20}]] (* Harvey P. Dale, Oct 24 2011 *)
PROG
(PARI) a(n)=if(n<0, 0, n!*polcoeff(log(1+x+x*O(x^n))*x/(1-x), n))
CROSSREFS
Sequence in context: A151370 A041567 A338084 * A292122 A264417 A348311
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Oct 20 2003
STATUS
approved

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Last modified March 28 13:35 EDT 2024. Contains 371254 sequences. (Running on oeis4.)