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A049509 Numbers k such that prime(k) == 7 (mod 10). 6
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 7 20:36 EDT 2021. Contains 343652 sequences. (Running on oeis4.)