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.
%I A236547 #19 Jul 30 2024 07:30:06 %S A236547 1,2,4,10,14,28,54,62,124,592,1088,3154,3920,5564,26510,28674,65124 %N A236547 Numbers k such that (2^(2k + 1) - 2)/3 + k - 1 is prime. %C A236547 These primes are represented in the numeral system described in A235860 with the digit "2" followed to the right with k-1 "12" strings. %e A236547 For n = 2, (2^5 - 2)/3 + 1 = 11, which is prime, so 2 is in the sequence. %o A236547 (PARI) isok(n) = isprime((2^(2*n+1) -2)/3 + n-1); \\ _Michel Marcus_, Jan 28 2014 %Y A236547 Cf. A235860. %K A236547 nonn %O A236547 1,2 %A A236547 _Robin Garcia_, Jan 28 2014 %E A236547 a(1) inserted and a(15)-a(17) from _Michael S. Branicky_, Jul 29 2024