cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A116467 Row squared sums of triangle A114700: a(n) = Sum_{k=0..n} A114700(n,k)^2.

Original entry on oeis.org

1, 2, 2, 4, 2, 4, 4, 8, 18, 52, 164, 544, 1852, 6416, 22520, 79888, 285938, 1031316, 3744628, 13676384, 50209860, 185190400, 685888736, 2549873880, 9511787452, 35592025904, 133559834064, 502494233128, 1895089009088, 7162963968712
Offset: 0

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Author

Paul D. Hanna, Feb 19 2006

Keywords

Crossrefs

Cf. A114700 (triangle), A116466 (unsigned row sums).

Programs

  • PARI
    {a(n)=sum(k=0,n,polcoeff(polcoeff(1/(1-x*y)+ x*(1+x-2*x^2*y)/(1-x)/(1+x+x*y+x*O(x^n)+y*O(y^k))/(1-x*y),n,x),k,y)^2)}

Formula

G.f.: A(x) = 2*(1-6*x+2*x^2+6*x^3+3*x^4)/(2-10*x-x^2)/(1-x)^2 + x*(2+x)*(1-4*x)/(2-10*x-x^2)/2*deriv(A(x)).