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 A075455 #15 Feb 18 2022 05:17:26 %S A075455 2203,77983,90863,185477,371087,388573,613607,912349,1293899,1600919, %T A075455 2146457,30661333,35608189,48823147,81190429,105823093,122753857, %U A075455 204341747,338602837,368601707,374788121,426958673,498675409,586371239,656232799,665360321,674509487,693132527 %N A075455 Prime averages of two successive perfect powers (A001597(k) + A001597(k+1))/2. %e A075455 2203 = (A001597(61)+A001597(62))/2 = (2197+2209)/2. %t A075455 a = Select[Range[2, 50000000], GCD @@ (Transpose[FactorInteger[ # ]][[2]]) > 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 (* _Tanya Khovanova_, Sep 15 2007 *) %Y A075455 Cf. A001597. %K A075455 easy,nonn %O A075455 1,1 %A A075455 _Zak Seidov_, Oct 11 2002 %E A075455 More terms from _Tanya Khovanova_, Sep 15 2007 %E A075455 More terms from _Amiram Eldar_, Feb 18 2022