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.

A218125 Number of 8-ary sequences with primitive period n.

Original entry on oeis.org

1, 8, 56, 504, 4032, 32760, 261576, 2097144, 16773120, 134217216, 1073709000, 8589934584, 68719210560, 549755813880, 4398044413896, 35184372055560, 281474959933440, 2251799813685240, 18014398375002624, 144115188075855864, 1152921503533101120
Offset: 0

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Author

Alois P. Heinz, Oct 21 2012

Keywords

Crossrefs

Column k=8 of A143324.

Programs

  • Maple
    with(numtheory):
    a:= n-> `if`(n=0, 1, add(8^d*mobius(n/d), d=divisors(n))):
    seq(a(n), n=0..30);

Formula

a(n) = Sum_{d|n} 8^d * mu(n/d) for n>0, a(0) = 1.
G.f.: 1 + 8 * Sum_{k>=1} mu(k) * x^k / (1 - 8*x^k). - Ilya Gutkovskiy, Apr 15 2021