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 A322969 #11 Jan 01 2019 12:39:56 %S A322969 2,5,7,11,13,16,21,23,25,31,35,37,39,42,49,51,53,55,58,60,65,73,75,77, %T A322969 80,82,84,86,88,97,99,101,105,107,113,115,117,119,121,124,134,136,138, %U A322969 140,144,147,149,151,153,155,157,160,162,164,166,168,179,181,188 %N A322969 Sum of the largest exponents A025479 of the first n perfect powers > 1. %H A322969 Hugo Pfoertner, <a href="/A322969/b322969.txt">Table of n, a(n) for n = 1..10000</a> %e A322969 a(1) = 2 because the first perfect power 4 = 2^2, %e A322969 a(2) = 5: added exponent 3 from 8 = 2^3, %e A322969 a(3) = 7: added exponent 2 from 9 = 3^2, %e A322969 a(4) = 11: added largest exponent 4 from 16=2^4. %t A322969 Union@ Accumulate@ Table[If[Set[e, GCD @@ #[[All, -1]]] > 1, e, 0] &@ FactorInteger@ n, {n, 4, 2400}] (* _Michael De Vlieger_, Jan 01 2019 *) %o A322969 (PARI) my(s=0); for(k=1, 3^7, if(j=ispower(k), print1(s+=j, ", "))) %Y A322969 Cf. A001597, A025479, A076408. %K A322969 nonn %O A322969 1,1 %A A322969 _Hugo Pfoertner_, Jan 01 2019