A291745 Nonprimes of the form 3*k + 1.

1, 4, 10, 16, 22, 25, 28, 34, 40, 46, 49, 52, 55, 58, 64, 70, 76, 82, 85, 88, 91, 94, 100, 106, 112, 115, 118, 121, 124, 130, 133, 136, 142, 145, 148, 154, 160, 166, 169, 172, 175, 178, 184, 187, 190, 196, 202, 205, 208, 214, 217, 220, 226, 232, 235, 238, 244, 247

Offset: 1

Author

Vincenzo Librandi, Aug 31 2017

Keywords

• nonn
• easy

Comments

Subsequence of A018252. A091300 is a subsequence.

A multiplicative semigroup: if m and n are in the sequence, then so is m*n. - Antti Karttunen, Jul 02 2024

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1600

Crossrefs

Cf. A002476, A016777, A091113, A091300, A291746, A291747, A373977 (characteristic function).

Programs

Magma

[n: n in [1..400 by 3] | not IsPrime(n)];

Mathematica

DeleteCases[3 Range[0, 300] + 1, _?PrimeQ]