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 A130640 #8 May 30 2025 09:41:14 %S A130640 2,3,4,5,11,12,13,14,19,23,24,26,57,61,96,106,175,189,226,227,311,312, %T A130640 373,483,741,1046,1298,1787,1952,2130,2285,2670,3254,3642,4369,4741, %U A130640 7082,8421,10695,13559,14802,18824,18892,20655,21653,33418,39937,66830,84160 %N A130640 Numbers k such that either 2^k + prime(k) or 2^k - prime(k) is prime. %e A130640 2^5 + p(5) = 32 + 11 = 43; 43 is prime, hence 5 is in the sequence. %e A130640 2^11 - p(11) = 2048 - 31 = 2017; 2017 is prime, therefore 11 is in the sequence. %t A130640 Select[Range[2000], PrimeQ[2^# - Prime[ # ]] || PrimeQ[2^# + Prime[ # ]] &] %Y A130640 Union of A077375 and A078583. %K A130640 nonn %O A130640 1,1 %A A130640 _J. M. Bergot_, Jun 19 2007 %E A130640 Edited and extended by _Stefan Steinerberger_, Jun 24 2007 %E A130640 a(45)-a(49) from _Michael S. Branicky_, May 30 2025