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.

A034349 Number of binary [ n,8 ] codes without 0 columns.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 8, 47, 277, 1775, 12616, 102445, 957357, 10174566, 119235347, 1482297912, 18884450721, 240477821389, 3012879828566, 36800049400028, 436068618826236, 5001537857507095, 55482177298724426, 595303034603214108, 6181562837200509792, 62170512250565592346
Offset: 1

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Comments

To find the g.f., modify the Sage program below (cf. function f). It is very complicated to write it here. - Petros Hadjicostas, Oct 07 2019

Crossrefs

Column k=8 of A034253 and first differences of A034362.

Programs

  • Sage
    # Fripertinger's method to find the g.f. of column k >= 2 of A034253 (for small k):
    def A034253col(k, length):
        G1 = PSL(k, GF(2))
        G2 = PSL(k-1, GF(2))
        D1 = G1.cycle_index()
        D2 = G2.cycle_index()
        f1 = sum(i[1]*prod(1/(1-x^j) for j in i[0]) for i in D1)
        f2 = sum(i[1]*prod(1/(1-x^j) for j in i[0]) for i in D2)
        f = f1 - f2
        return f.taylor(x, 0, length).list()
    # For instance the Taylor expansion for column k = 8 (current sequence) gives
    print(A034253col(8, 30)) # Petros Hadjicostas, Oct 07 2019

Extensions

More terms from Petros Hadjicostas, Oct 07 2019