A072125 Concatenation of first n entries (digits) of A007376 is not divisible by 3.

1, 4, 7, 10, 11, 12, 14, 16, 17, 18, 20, 22, 23, 24, 26, 28, 29, 32, 34, 35, 38, 40, 41, 44, 46, 47, 53, 54, 59, 60, 65, 66, 70, 71, 72, 74, 76, 77, 78, 80, 82, 83, 84, 86, 88, 89, 92, 94, 95, 98, 100, 101, 104, 106, 107, 113, 114, 119, 120, 125, 126, 130, 131, 132, 134

Offset: 1

Author

Lekraj Beedassy, Jun 20 2002

Keywords

• easy
• nonn
• base

Comments

Concatenation of some permutations of the n digits of A007376 is likely to be prime.

Examples

			16 is in the sequence because the 16-digit number 1234567891011121 = 1 (mod 3).
		

Crossrefs

Cf. A007376 & A033307.

Programs

Mathematica

f[0] = 0; f[n_Integer] := 10^(Floor[Log[10, n]] + 1)*f[n - 1] + n; Select[ Range[140], Mod[ FromDigits[ Take[ IntegerDigits[ f[n]], n]], 3] != 0 &]

Extensions

Edited by Robert G. Wilson v, Jun 21 2002