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.

A185954 G.f.: A(x) = exp( Sum_{n>=1} A163659(2n)*x^n/n ), where x*exp(Sum_{n>=1} A163659(n)*x^n/n) = S(x) is the g.f. of Stern's diatomic series (A002487).

Original entry on oeis.org

1, 3, 8, 13, 23, 32, 49, 59, 80, 93, 127, 144, 185, 203, 256, 269, 319, 328, 401, 419, 504, 525, 639, 656, 761, 763, 904, 917, 1063, 1064, 1241, 1227, 1368, 1317, 1503, 1480, 1681, 1659, 1928, 1909, 2143, 2080, 2393, 2371, 2696, 2653, 3055, 2992, 3305, 3147
Offset: 0

Views

Author

Paul D. Hanna, Feb 07 2011

Keywords

Comments

Compare with g.f. of A171238: exp( Sum_{n>=1} A163659(3n)*x^n/n ).

Examples

			G.f.: A(x) = 1 + 3*x + 8*x^2 + 13*x^3 + 23*x^4 + 32*x^5 + 49*x^6 +...
log(A(x)) = 3*x + 7*x^2/2 - 6*x^3/3 + 15*x^4/4 + 3*x^5/5 - 14*x^6/6 + 3*x^7/7 + 31*x^8/8 - 6*x^9/9 +...+ A163659(2n)*x^n/n +...
		

Crossrefs

Programs

  • PARI
    {A002487(n)=local(c=1, b=0); while(n>0, if(bitand(n, 1), b+=c, c+=b); n>>=1); b}
    {A163659(n)=n*polcoeff(log(sum(k=0, n, A002487(k+1)*x^k)+x*O(x^n)), n)}
    {a(n)=polcoeff(exp(sum(k=1, n, A163659(2*k)*x^k/k)+x*O(x^n)), n)}

Formula

G.f. satisfies: A(x) = A(x^2)*(1+x)*(1-x^3)^2/[(1-x)^2*(1+x^3)].