A049509 Numbers k such that prime(k) == 7 (mod 10).

4, 7, 12, 15, 19, 25, 28, 31, 33, 37, 39, 45, 49, 55, 59, 63, 66, 68, 69, 73, 78, 88, 91, 93, 101, 102, 106, 107, 111, 113, 118, 123, 129, 134, 138, 139, 144, 148, 151, 154, 155, 159, 161, 163, 165, 168, 181, 184, 187, 195, 199, 203, 206, 211, 214, 217, 219, 225

Offset

1,1

Comments

The asymptotic density of this sequence is 1/4 (by Dirichlet's theorem). - Amiram Eldar, Mar 01 2021

Links

Table of n, a(n) for n=1..58.

Formula

a(n) = A000720(A030432(n)). - Ray Chandler, Nov 07 2006

Mathematica

Select[Range[240], Mod[Prime[ # ], 10] == 7 &] (* Ray Chandler, Nov 07 2006 *)

Crossrefs

Cf. A000720, A030432, A102342.

Cf. A049508, A049510, A049511.

Sequence in context: A310771 A310772 A244741 * A026360 A237514 A276888

Adjacent sequences: A049506 A049507 A049508 * A049510 A049511 A049512

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Extended by Ray Chandler, Nov 07 2006

Status

approved