A262687 a(n) = index of first n in A262680; positions of records in A262680.

0, 1, 4, 169, 324, 1521, 125316, 126025, 425104, 1713481, 1716100, 4959529, 24760576

Offset: 0

Author

Antti Karttunen, Oct 03 2015

Keywords

• nonn
• more

Comments

All terms are squares (A262688 gives the square roots).

The even and odd terms alternate.

Crossrefs

Cf. A262680, A261088, A262514.

Cf. A262688 (square roots of these terms).

Programs

PARI

allocatemem((2^31)+(2^30));
uplim = 2^25;
v262680 = vector(uplim);
v262680[1] = 1; v262680[2] = 0;
for(i=3, uplim, v262680[i] = issquare(i) + v262680[i-numdiv(i)];
if(!(i%65536),print1(i,", ")););
A262680 = n -> if(!n,n,v262680[n]);
n=0; k=0; while(n*n <= uplim, if(A262680(n*n)==k, write("b262687.txt", k, " ", n*n); k++); n++;);

Scheme

;; With Antti Karttunen's IntSeq-library.
(define A262687 (RECORD-POS 0 0 A262680))