A125227 A014741(n)/6 for n>2.

1, 3, 7, 9, 21, 27, 49, 57, 63, 81, 147, 171, 189, 219, 243, 301, 343, 399, 441, 513, 567, 657, 729, 889, 903, 1029, 1083, 1197, 1323, 1533, 1539, 1701, 1971, 2107, 2187, 2359, 2401, 2667, 2709, 2793, 3087, 3249, 3591, 3969, 4161, 4401, 4599, 4617, 5103, 5913

Offset: 3

Author

Alexander Adamchuk, Jan 15 2007

Keywords

• nonn

Comments

A014741(n) is divisible by 6 for n>2.

All powers of 3 are terms. All powers of 7 are terms. The prime divisors of terms of this sequence (for n up to 10^6) in order of their first appearance are 3, 7, 19, 73, 43, 127, 337, 163, 379, 571, 5419, 487, 2593, 439, 1459, 431, 883.

The sequence is multiplicative in the sense that if two numbers k and m are terms, then k*m is too.

Examples

			a(3) = A014741(3)/6 = 6/6 = 1.
a(4) = A014741(4)/6 = 18/6 = 3.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 3..10000

Crossrefs

Cf. A014741, A000295, A086787.

Programs

Mathematica

Select[Range[3,6000], PowerMod[2,#+1,# ]==2&]/6

Formula

a(n) = A014741(n)/6 = A014945(n-1)/3. - Max Alekseyev, Nov 14 2012