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A290581
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Column 1 of triangle A290580.
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3
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1, 20, 364, 7028, 148752, 3471192, 89097664, 2503362488, 76575071488, 2536513162508, 90532686154752, 3465845396598540, 141726054915248128, 6167370619705004144, 284635248765764878336, 13889365886508877963184, 714612366728939248091136, 38667882915659893417754820, 2195406208657284278474506240, 130509259754593318496376665060, 8107405596523654695095077175296, 525358015896796804145274761270600
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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a(n) ~ c * n^(n+2), where c = (exp(5) - 4*exp(3) - exp(1))/16 = 4.0845455988354304513775733719295... - Vaclav Kotesovec, Aug 21 2017
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PROG
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(PARI) /* As column 1 of triangle A290580 */
{ A290580(n, k) = my(W=1, E=1, S=x, C=1, D=1); for(i=0, n,
S = intformal(C*D +x*O(x^n)) ;
C = 1 - intformal(S*D) ; D = 1 - m*intformal(S*C) ;
E = subst( (1 + S)/C, m, 1-m) ) ;
for(i=0, n, W = subst(E, x, x*W));
n!*polcoeff(polcoeff(W, n, x), k, m) }
for(n=1, 25, print1( A290580(n+2, 1), ", "))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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