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Search: id:A135457
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| A135457 |
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a(n)=(-1/4)prod(i=1,n,2i-3){(2n-1)Pi+2(-1)^n*sum(k=0,infty,k!/prod(j=1,k,2j+2n-1))). |
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+0
1
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| 0, 3, 10, 91, 684, 8679, 100542, 1664055, 25991640, 532354635, 10455799410, 255542155155, 6044821114500, 171748491958575, 4751436512960550, 153911731348760175, 4874807783839316400, 177334729873063945875
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n) satisfies the order 3 recurrence : a(1)=0, a(2)=3, a(3)=10 and for n>=1 a(n+3)=4a(n+2)+(4n^2+12n+1)a(n+1)-(8n^2-2)a(n)
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PROGRAM
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(PARI) a(n)=round((-1/4)*prod(i=1, n, 2*i-3)*(Pi*(2*n-1)+2*(-1)^n*sum(k=0, 1500, 1.*k!/prod(i=1, k, (2*i+2*n-1)))))
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CROSSREFS
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Adjacent sequences: A135454 A135455 A135456 this_sequence A135458 A135459 A135460
Sequence in context: A136505 A006311 A034792 this_sequence A073733 A005205 A065924
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KEYWORD
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nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Dec 15 2007
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