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A354659
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A diagonal of triangle A354650: a(n) = A354650(n,n+1), for n >= 0.
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5
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1, 3, 30, 390, 5928, 98910, 1757688, 32683680, 628884300, 12428334215, 250940544738, 5156722096422, 107538413657010, 2270751678647100, 48464836803383400, 1044050265679857144, 22675350105240015204, 496034970650911331550, 10920742396832034391590
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) ~ c * d^n / n^2, where d = 24.5759928778699928131449756... and c = 0.35661791857107638456206... - Vaclav Kotesovec, Mar 19 2023
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PROG
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(PARI) {A354650(n, k) = my(A=[1+y]); for(i=1, n, A = concat(A, 0);
A[#A] = polcoeff(y + sum(m=0, sqrtint(2*#A+9), (-1)^m * x^(m*(m-1)/2) * (1 - x^(2*m+1)) * Ser(A)^(m*(m+1)/2) ), #A-1) );
polcoeff(A[n+1], k, y)}
for(n=0, 20, print1(A354650(n, n+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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