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A133941
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E.g.f. satisfies: A(x) = x*(exp(tan(A(x)))).
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1
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0, 1, 2, 9, 72, 825, 12192, 220353, 4708480, 116116497, 3245839360, 101415497689, 3502465714176, 132486192976137, 5447446920323072, 241907419042038225, 11538444129924055040, 588321821566662253729, 31932991994214557417472
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| Alois P. Heinz, Table of n, a(n) for n = 0..100
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FORMULA
| a(n) = sum(k=1..n-1, (n^k*((-1)^(n-k-1)+1)*sum(j=k..n-1, C(j-1,k-1)*j!*2^(n-j-2) * (-1)^((n+k-1)/2+j)*stirling2(n-1,j),j,k,n-1))/k!) n>1. a(1)=1. [Vladimir Kruchinin, May 10 2011
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MAPLE
| A:= proc(n) option remember; if n=0 then 0 else convert (series (x* (exp (tan(A(n-1)))), x=0, n+1), polynom) fi end: a:= n-> coeff (A(n), x, n)*n!: seq (a(n), n=0..22);
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PROG
| (Maxima) a(n):=if n<2 then n else sum((n^k*((-1)^(n-k-1)+1)*sum(binomial(j-1, k-1)*j!*2^(n-j-2)*(-1)^((n+k-1)/2+j)*stirling2(n-1, j), j, k, n-1))/k!, k, 1, n-1) [Vladimir Kruchinin, May 10 2011]
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CROSSREFS
| Sequence in context: A193469 A121879 A118789 * A038035 A133984 A108995
Adjacent sequences: A133938 A133939 A133940 * A133942 A133943 A133944
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KEYWORD
| nonn
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AUTHOR
| Alois P. Heinz (heinz(AT)hs-heilbronn.de), Aug 27 2008
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