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A262687 a(n) = index of first n in A262680; positions of records in A262680. 4
0, 1, 4, 169, 324, 1521, 125316, 126025, 425104, 1713481, 1716100, 4959529, 24760576 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

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

The even and odd terms alternate.

LINKS

Table of n, a(n) for n=0..12.

PROG

(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))

CROSSREFS

Cf. A262680, A261088, A262514.

Cf. A262688 (square roots of these terms).

Sequence in context: A024265 A302453 A061710 * A177005 A017414 A051476

Adjacent sequences:  A262684 A262685 A262686 * A262688 A262689 A262690

KEYWORD

nonn,more

AUTHOR

Antti Karttunen, Oct 03 2015

STATUS

approved

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Last modified September 23 03:04 EDT 2020. Contains 337291 sequences. (Running on oeis4.)