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.

A147557 Result of using the primes as coefficients in an infinite polynomial series in x and then expressing this series as (1+a(1)x)(1+a(2)x^2)(1+a(3)x^3)...

Original entry on oeis.org

2, 3, -1, 9, -4, 0, -16, 89, -52, 60, -182, 214, -620, 966, -2142, 10497, -7676, 13684, -27530, 48288, -98372, 190928, -364464, 619496, -1341508, 2649990, -4923220, 9726940, -18510902, 37055004, -69269976, 213062855, -258284232, 527143794
Offset: 1

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Author

Neil Fernandez, Nov 07 2008

Keywords

Examples

			From the primes, construct the series 1+2x+3x^2+5x^3+7x^4+... a(1) is always the coefficient of x, here 2. Divide by (1+2x) to get the quotient (1+a(2)x^2+...), which here gives a(2)=3. Then divide this quotient by (1+a(2)x^2), i.e. here (1+3x^2), to get (1+a(3)x^3+...), giving a(3)=-1.
		

Crossrefs

Programs

  • Mathematica
    ser=1+Sum[Prime[i]x^i,{i,110}];ss=1+2x;Do[ser=Normal[Series[ser/(Take[ser,2]),{x,0,105}]];ss+=ser[[2]],{100}];A147557=CoefficientList[ss,x] (* Zak Seidov, Nov 10 2008 *)

Extensions

Corrected and extended by Zak Seidov, Nov 10 2008