A185708 Characteristic function of positive numbers that are primes ending in 7.

0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

Mathematica

Table[If[PrimeQ[n]&&Mod[n, 10]==7, 1, 0], {n, 120}] (* Harvey P. Dale, Aug 11 2019 *)

Prog

(PARI) A185708(n) = ((7==(n%10))&&isprime(n)); \\ Antti Karttunen, Oct 09 2018

Crossrefs

Cf. A030432 (primes of form 10n+7).

Sequence in context: A103674 A358842 A358758 * A373256 A286996 A044937

Adjacent sequences: A185705 A185706 A185707 * A185709 A185710 A185711

Keyword

base,nonn

Author

N. J. A. Sloane, Feb 10 2011

Status

approved