A198778 Primes from merging of 4 successive digits in decimal expansion of Euler-Mascheroni constant A001620.

577, 421, 3359, 3593, 5939, 9923, 8677, 2677, 6709, 6947, 6329, 2917, 4951, 1447, 401, 4283, 2417, 6449, 5003, 3733, 3767, 7673, 9491, 2039, 853, 5323, 6211, 4793, 7937, 857, 7057, 29, 3547, 6043, 587, 6733, 7331, 3313, 1399, 7541, 5413, 4139, 8423, 4877, 503, 8431, 3109, 1093, 9973, 3613, 8893, 8933, 17, 7247

Offset: 1

Author

Harvey P. Dale, Oct 29 2011

Keywords

• nonn
• base

Comments

In contrast to A104938, leading zeros are allowed here, which explains the terms having fewer than 4 digits; e.g., a(32)=29 comes from consecutive digits "...0029..." starting at the 268th decimal digit of gamma (if the initial "0." counts as the first digit). - M. F. Hasler, Oct 31 2011

Examples

			The first four decimal digits of gamma = 0.5772... form the prime 577=a(1).
		

Crossrefs

Cf. A103773, A103789, A103793, A103808-A103812, A104824-A104826, A104843-A104850, A198161-A198177, A198776-A198784.

Programs

Maple

Digits := 420 ;
for sh from 3 do
        p := floor(gamma*10^sh) mod 10000 ;
        if isprime(p) then
                printf("%d,",p);
        end if;
end do: # R. J. Mathar, Oct 31 2011

Mathematica

(* see A104938 for Mmca code *)
Join[{577},Select[FromDigits/@Partition[RealDigits[EulerGamma,10,1000][[1]],4,1],PrimeQ]] (* Harvey P. Dale, May 07 2019 *)

PARI

L=10^4;for(i=3,999,isprime(p=Euler\.1^i%L)&print1(p",")) \\ M. F. Hasler, Oct 31 2011