A166103 -id:A166103 - cp's OEIS frontend

A166102 Odd numbers k such that A166100((k-1)/2)/k is not an integer.

3, 27, 75, 243, 363, 675, 867, 1587, 1875, 2187, 2523, 3267, 5043, 6075, 6627, 7803, 8427, 9075, 10443, 14283, 15123, 16875, 19683, 20667, 21675, 22707, 23763, 29403, 30603, 34347, 38307, 39675, 43923, 45387, 46875, 51483, 54675

Offset: 1

Antti Karttunen, Oct 13 2009

nonn

Conjecture: a(n) = 3*A166103(n). (Checked for terms a(1)-a(92).)

A. Karttunen, Table of n, a(n) for n = 1..92

a(n) = A005408(A166101(n)). Cf. A166272.

A166104 Natural numbers whose prime factors are all congruent to 3 or 5 mod 6 (i.e., are in the sequence A045410).

Original entry on oeis.org

1, 3, 5, 9, 11, 15, 17, 23, 25, 27, 29, 33, 41, 45, 47, 51, 53, 55, 59, 69, 71, 75, 81, 83, 85, 87, 89, 99, 101, 107, 113, 115, 121, 123, 125, 131, 135, 137, 141, 145, 149, 153, 159, 165, 167, 173, 177, 179, 187, 191, 197, 205, 207, 213, 225, 227, 233, 235, 239

Offset: 1

Antti Karttunen, Oct 13 2009

nonn

1 is included, as it has no prime factors at all, thus no prime factors outside of A045410.

A. Karttunen, Table of n, a(n) for n = 1..1001

See the conjecture at A166103. Cf. A045410.

cp's OEIS Frontend

A166102 Odd numbers k such that A166100((k-1)/2)/k is not an integer.

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