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.

A035083 DIK(b)-DIK[ 2 ](b)-b where b is A035082.

Original entry on oeis.org

0, 0, 0, 1, 1, 2, 3, 7, 14, 33, 74, 180, 438, 1090, 2741, 6994, 17966, 46565, 121440, 318597, 839953, 2224486, 5914248, 15780662, 42241422, 113402369, 305254039, 823690961, 2227640597, 6037142355, 16392945284, 44592703836
Offset: 0

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Author

Christian G. Bower, Nov 15 1998

Keywords

Crossrefs

Programs

  • PARI
    BIK(p)={(1/(1-p) + (1+p)/subst(1-p, x, x^2))/2}
    DIK(p,n)={(sum(d=1, n, eulerphi(d)/d*log(subst(1/(1+O(x*x^(n\d))-p), x, x^d))) + ((1+p)^2/(1-subst(p, x, x^2))-1)/2)/2}
    EulerT(v)={Vec(exp(x*Ser(dirmul(v, vector(#v, n, 1/n))))-1, -#v)}
    seq(n)={my(p=O(x)); for(n=1, n, p=x+x^2*Ser(EulerT(Vec(BIK(p)-1)-Vec(p)))); Vec(DIK(p, n) - p - (p^2 + subst(p, x, x^2))/2, -(n+1))} \\ Andrew Howroyd, Aug 31 2018