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 A131697 #8 Feb 18 2022 05:17:13 %S A131697 101,577,677,2203,15877,22501,25609,32401,42061,57601,72901,181501, %T A131697 228211,324901,378229,394393,462409,695581,804709,1664101,1742401, %U A131697 1971241,2873029,3062509,3186229,4137181,4305661,4347229,4804889,5336101,6200269,6502501,7177693,7209229 %N A131697 Prime averages of two successive perfect prime powers. %H A131697 Amiram Eldar, <a href="/A131697/b131697.txt">Table of n, a(n) for n = 1..1000</a> %e A131697 101 is the average of 81 and 121. %t A131697 a = Select[ Range[2, 10000000], ! PrimeQ[ # ] && Length[FactorInteger[ # ]] == 1 &]; sizea = Length[a]; (a[[Select[Range[sizea - 1], PrimeQ[(a[[ # ]] + a[[ # + 1]])/2] &]]] + a[[Select[Range[sizea - 1], PrimeQ[(a[[ # ]] + a[[ # + 1]])/2] &] + 1]])/2 %Y A131697 Cf. A000961, A075455 (Prime averages of two successive perfect powers). %K A131697 nonn %O A131697 1,1 %A A131697 _Tanya Khovanova_, Sep 15 2007 %E A131697 More terms from _Amiram Eldar_, Feb 18 2022