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.

A218025 Shifts 8 places left under Euler transform with a(0)=0 and a(n)=1 for n<8.

Original entry on oeis.org

0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 43, 59, 85, 118, 170, 241, 349, 500, 728, 1051, 1534, 2226, 3252, 4735, 6929, 10117, 14829, 21715, 31893, 46828, 68920, 101442, 149589, 220650, 325939, 481659, 712605, 1054747, 1562670, 2316296, 3436200
Offset: 0

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Author

Alois P. Heinz, Oct 18 2012

Keywords

Crossrefs

Column k=8 of A144018.
Cf. A316080.

Programs

  • Maple
    with(numtheory):
    b:= proc(n) option remember; `if`(n=0, 1,
          (add(add(d*a(d), d=divisors(j))*b(n-j), j=1..n))/n)
        end:
    a:= n-> `if`(n<8, signum(n), b(n-8)):
    seq(a(n), n=0..50);

Formula

G.f.: x + x^2 + x^3 + x^4 + x^5 + x^6 + x^7 + x^8 / Product_{n>=1} (1 - x^n)^a(n). - Ilya Gutkovskiy, May 08 2019