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A104938 Primes from merging of 4 successive digits in decimal expansion of the Euler-Mascheroni constant A001620.

%I A104938 #23 Feb 16 2025 08:32:57
%S A104938 3359,3593,5939,9923,8677,2677,6709,6947,6329,2917,4951,1447,4283,
%T A104938 2417,6449,5003,3733,3767,7673,9491,2039,5323,6211,4793,7937,7057,
%U A104938 3547,6043,6733,7331,3313,1399,7541,5413,4139,8423,4877,8431,3109,1093,9973,3613
%N A104938 Primes from merging of 4 successive digits in decimal expansion of the Euler-Mascheroni constant A001620.
%C A104938 Leading zeros are not permitted, so each term is 4 digits in length.
%H A104938 Vincenzo Librandi, <a href="/A104938/b104938.txt">Table of n, a(n) for n = 1..1000</a>
%H A104938 Jon Borwein, <a href="https://web.archive.org/web/20060212094503/http://www.worldwideschool.org/library/books/sci/math/MiscellaneousMathematicalConstants/chap35.html">170,000 digits of Gamma</a> [Wayback Machine copy]
%H A104938 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Euler-MascheroniConstant.html">Euler-Mascheroni Constant</a>.
%p A104938 Digits := 420 ;
%p A104938 for sh from 3 do
%p A104938         p := floor(gamma*10^sh) mod 10000 ;
%p A104938         if isprime(p) and p > 999 then
%p A104938                 printf("%d,",p);
%p A104938         end if;
%p A104938 end do: # _R. J. Mathar_, Oct 31 2011
%t A104938 egp[len_]:=Module[{egterms=FromDigits/@Partition[RealDigits[EulerGamma, 10, 1000][[1]],len,1]},Select[egterms,IntegerLength[#]==len&&PrimeQ[#]&]]; egp[4] (* _Harvey P. Dale_, Oct 29 2011 *)
%o A104938 (PARI) L=10^4;for(i=3,999,isprime(p=Euler\.1^i%L)&p*10>L&print1(p",")) \\ _M. F. Hasler_, Oct 31 2011
%Y A104938 Cf. A198778.
%Y A104938 Cf. A103773, A103789, A103793, A103808 - A103812, A104824- A104826, A104843 - A104850, A198161 - A198177, A198776 - A198784. - _Harvey P. Dale_, Oct 29 2011
%K A104938 nonn,base
%O A104938 1,1
%A A104938 Andrew G. West (WestA(AT)wlu.edu), Mar 29 2005
%E A104938 Offset changed from 0 to 1 by _Vincenzo Librandi_, Apr 21 2013