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.

A299382 Numbers k such that k * 19^k - 1 is prime.

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%I A299382 #17 Nov 24 2024 04:09:16
%S A299382 12,410,33890,91850,146478,189620,280524
%N A299382 Numbers k such that k * 19^k - 1 is prime.
%C A299382 a(8) > 400000.
%H A299382 Steven Harvey, <a href="http://harvey563.tripod.com/GeneralizedWoodallPrimes.txt">Generalized Woodall Search</a>.
%H A299382 Wikipedia, <a href="https://en.wikipedia.org/wiki/Woodall_number">Woodall number</a>.
%t A299382 Select[Range[1, 10000], PrimeQ[n*19^n-1] &]
%o A299382 (PARI) for(n=1, 10000, if(isprime(n*19^n-1), print1(n", ")))
%o A299382 (Magma) [n: n in [1..10000] |IsPrime(n*19^n-1)];
%Y A299382 Numbers n such that n * b^n - 1 is prime: A008864 (b=1), A002234 (b=2), A006553 (b=3), A086661 (b=4), A059676 (b=5), A059675 (b=6), A242200 (b=7), A242201 (b=8), A242202 (b=9), A059671 (b=10), A299374 (b=11), A299375 (b=12), A299376 (b=13), A299377 (b=14), A299378 (b=15), A299379 (b=16), A299380 (b=17), A299381 (b=18), this sequence (b=19), A299383 (b=20).
%K A299382 nonn,more,hard
%O A299382 1,1
%A A299382 _Tim Johannes Ohrtmann_, Feb 08 2018