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.

A173241 Euler transform of A051064, the ruler function sequence for k=3.

Original entry on oeis.org

1, 1, 2, 4, 6, 9, 16, 22, 33, 51, 71, 100, 147, 199, 275, 384, 515, 692, 944, 1242, 1645, 2186, 2847, 3706, 4848, 6231, 8019, 10330, 13153, 16729, 21305, 26864, 33858, 42658, 53366, 66668, 83277, 103378, 128200, 158846, 195895, 241237, 296860, 363796, 445285, 544465, 663520
Offset: 0

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Author

Gary W. Adamson, Feb 13 2010

Keywords

Comments

Let P(x) = polcoeff A000041: (1 + x + 2x^2 + 3x^3 + 5x^4 + 7x^5 + ...) and
A(x) = polcoeff A173241: (1 + x + 2x^2 + 4x^3 + 6x^4 + 9x^5 + ...); then
P(x) = A(x) / A(x^3).
A092119 = Euler transform of the ruler function for k=2: A001511.

Examples

			Equals 1/((1-x)*(1-x^2)*(1-x^3)^2*(1-x^4)*(1-x^5)*(1-x^6)^2*(1-x^7)*...); where in (1-x)^k, k = A051064: (1, 1, 2, 1, 1, 2, 1, 1, 3, ...).
		

Crossrefs

Programs

  • PARI
    N=66; x='x+O('x^N); /* that many terms */
    gf=1/prod(e=0, ceil(log(N)/log(3)), eta(x^(3^e)));
    Vec(gf) /* show terms */ /* Joerg Arndt, Jun 21 2011 */

Formula

G.f.: 1/Product_{k>=0} P(x^(3^k)) where P(x)=Product_{k>=1} (1-x^k). - Joerg Arndt, Jun 21 2011
Euler transform of A051064, where A051064 = the ruler function for k=3:
(1, 1, 2, 1, 1, 2, 1, 1, 3, 1, 1, 2, ...).

Extensions

More terms from Joerg Arndt, Jun 21 2011