A173800 -id:A173800 - cp's OEIS frontend

A173801 The number of primitive numbers k such that 1/k is in the Cantor set and the fraction 1/k has period n.

1, 1, 1, 2, 1, 3, 1, 4, 2, 3, 1, 9, 1, 3, 3, 9, 1, 14, 1, 12, 3, 3, 1, 28, 2, 3, 5, 9, 1, 32, 1, 17, 3, 3, 3, 50, 1, 3, 5, 31, 1, 32, 1, 9, 14, 4, 1, 97, 2, 10, 3, 9, 1, 57, 4, 27, 3, 4, 1, 160, 1, 3, 9, 34, 3, 32, 1, 9, 3, 23, 1, 193, 1, 3, 10, 9, 3, 51, 1, 102, 9, 3, 1, 148, 3, 3, 3, 28, 1, 255, 3

Offset: 1

T. D. Noe, Feb 25 2010

nonn

See A173800 for the numbers k for each n.

T. D. Noe, Table of n, a(n) for n=1..200

A175174 Least primitive number k such that 1/k is in the Cantor set and the fraction 1/k has period n in base 3.

Original entry on oeis.org

1, 4, 13, 10, 121, 28, 1093, 82, 757, 244, 88573, 730, 797161, 2188, 59293, 6562, 64570081, 1036, 581130733, 2362, 4785157, 177148, 47071589413, 84253, 3501192601, 1594324, 387440173, 4782970, 34315188682441, 66124

Offset: 1

T. D. Noe, Feb 28 2010

nonn

Primitive means that 3 does not divide k. The term a(n) is the first term in row n of A173800. For n=p^k, with p prime and k>0, it appears that a(n) = Phi(n,3), the n-th cyclotomic polynomial evaluated at 3.

T. D. Noe, Table of n, a(n) for n=1..200

cp's OEIS Frontend

A173801 The number of primitive numbers k such that 1/k is in the Cantor set and the fraction 1/k has period n.

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