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.

A100605 Numbers k such that (prime(k)-1)! + prime(k)^2 is prime.

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%I A100605 #16 Jul 02 2024 14:19:18
%S A100605 1,2,4,10,26
%N A100605 Numbers k such that (prime(k)-1)! + prime(k)^2 is prime.
%C A100605 k = {1, 2, 4, 10, 26} yields primes p(k) = {2, 3, 7, 29, 101}. There are no more such k up to k=100. Verified by Ray Chandler.
%C A100605 a(6) > 750. - _Jinyuan Wang_, Apr 10 2020
%C A100605 a(5) > 2500. - _Michael S. Branicky_, Jul 02 2024
%F A100605 Numbers k such that (prime(k)-1)! + prime(k)^2 is prime, where prime(k) is the k-th prime.
%e A100605 a(3) = 4 because (prime(4)-1)! + prime(4)^2 = (7-1)! + 7^2 = 720 + 49 = 769 is prime and is the 3rd such prime of that form.
%o A100605 (PARI) is(k) = ispseudoprime((prime(k)-1)! + prime(k)^2); \\ _Jinyuan Wang_, Apr 10 2020
%Y A100605 Cf. A100604, A100858.
%K A100605 nonn,hard,more
%O A100605 1,2
%A A100605 _Jonathan Vos Post_, Nov 30 2004