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 A262687 #11 Apr 28 2025 15:12:12
%S A262687 0,1,4,169,324,1521,125316,126025,425104,1713481,1716100,4959529,
%T A262687 24760576
%N A262687 a(n) = index of first n in A262680; positions of records in A262680.
%C A262687 All terms are squares (A262688 gives the square roots).
%C A262687 The even and odd terms alternate.
%o A262687 (PARI)
%o A262687 allocatemem((2^31)+(2^30));
%o A262687 uplim = 2^25;
%o A262687 v262680 = vector(uplim);
%o A262687 v262680[1] = 1; v262680[2] = 0;
%o A262687 for(i=3, uplim, v262680[i] = issquare(i) + v262680[i-numdiv(i)];
%o A262687 if(!(i%65536),print1(i,", ")););
%o A262687 A262680 = n -> if(!n,n,v262680[n]);
%o A262687 n=0; k=0; while(n*n <= uplim, if(A262680(n*n)==k, write("b262687.txt", k, " ", n*n); k++); n++;);
%o A262687 (Scheme)
%o A262687 ;; With _Antti Karttunen_'s IntSeq-library.
%o A262687 (define A262687 (RECORD-POS 0 0 A262680))
%Y A262687 Cf. A262680, A261088, A262514.
%Y A262687 Cf. A262688 (square roots of these terms).
%K A262687 nonn,more
%O A262687 0,3
%A A262687 _Antti Karttunen_, Oct 03 2015