cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A102343 Numbers k such that k*10^3 + 777 is prime.

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%I A102343 #29 Feb 13 2025 16:26:13
%S A102343 1,2,11,19,22,26,41,43,44,47,50,53,65,67,68,71,76,79,80,83,94,97,107,
%T A102343 110,113,115,122,124,125,131,134,136,137,145,146,152,155,158,167,169,
%U A102343 170,173,176,181,184,199,202,211,212,226,229,232,233,250,253,254,268,272,274,281,284,286,292,295,298,299
%N A102343 Numbers k such that k*10^3 + 777 is prime.
%C A102343 From Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009: (Start)
%C A102343 The sequence is infinite by Dirichlet's theorem about primes in arithmetic progression.
%C A102343 No term of the sequence is of form 3k, because the sum of digits of 10^3*3k + 333 = 3*(10^3 + 259) is divisible by 3, violating the requirement of the definition. (End)
%H A102343 Harvey P. Dale, <a href="/A102343/b102343.txt">Table of n, a(n) for n = 1..1000</a>
%e A102343 k=1: 1*10^3 + 777 = 1777 is prime, hence 1 is in the sequence.
%e A102343 k=50: 50*10^3 + 777 = 50777 is prime, hence 50 is in the sequence.
%e A102343 k=97: 97*10^3 + 777 = 97777 is prime, hence 97 is in the sequence.
%t A102343 Select[Range[300],PrimeQ[1000#+777]&] (* _Harvey P. Dale_, Jun 06 2022 *)
%o A102343 (Magma) [ n: n in [0..300] | IsPrime(n*10^3+777) ];
%o A102343 (PARI) is(n)=isprime(n*10^3+777) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y A102343 Cf. A157772, A102248, A159942, A102611.
%K A102343 nonn,base,easy
%O A102343 1,2
%A A102343 _Parthasarathy Nambi_, Feb 20 2005
%E A102343 Extended by Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009
%E A102343 Edited by _R. J. Mathar_, Apr 30 2009
%E A102343 More terms from _Vincenzo Librandi_, May 01 2009