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A198778 Primes from merging of 4 successive digits in decimal expansion of Euler-Mascheroni constant A001620. 11
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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

LINKS

Table of n, a(n) for n=1..54.

EXAMPLE

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

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 *)

PROG

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

CROSSREFS

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

Sequence in context: A159055 A064031 A013911 * A198777 A104937 A234105

Adjacent sequences:  A198775 A198776 A198777 * A198779 A198780 A198781

KEYWORD

nonn,base

AUTHOR

Harvey P. Dale, Oct 29 2011

STATUS

approved

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Last modified October 14 09:25 EDT 2019. Contains 327995 sequences. (Running on oeis4.)