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A322196
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a(n) = [x^(n+1)*y^n/((n+1)!*n!)] (cosh(x)*cosh(y) + sinh(x) + sinh(y)) / (1 - sinh(x)*sinh(y)), for n >= 0.
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4
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1, 2, 14, 200, 4808, 174752, 8948384, 614111360, 54420050048, 6049980273152, 824598462370304, 135229597964011520, 26270107716700325888, 5966042534096492797952, 1566190258767667468673024, 470646643220470846599495680, 160520698699963165307893219328, 61671685329051568727390505009152, 26512964135663506964369113425772544, 12678129819059978095225581054619811840
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(n) ~ c * n^(2*n + 3/2) / (exp(2*n) * (log(1+sqrt(2)))^(2*n)), where c = 10.51378195853429294422318592930043390... - Vaclav Kotesovec, Dec 31 2018
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PROG
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(PARI) {A322190(n, k) = my(X=x+x*O(x^n), Y=y+y*O(y^k));
C = cosh(X)*cosh(Y)/(1 - sinh(X)*sinh(Y));
S = (sinh(X) + sinh(Y))/(1 - sinh(X)*sinh(Y));
n!*k!*polcoeff(polcoeff( C + S, n, x), k, y)}
for(n=0, 20, print1( A322190(n+1, n), ", "))
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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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