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A287617 Main diagonal of A045847. 9
1, 1, 1, 1, 5, 21, 61, 141, 309, 766, 2191, 6436, 18041, 48348, 128311, 347166, 960197, 2674883, 7413514, 20411986, 56130675, 154907229, 429349768, 1192532452, 3312339849, 9196063371, 25538113056, 70994900341, 197595884071, 550414483911, 1533911418946 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

a(n) is the number of representations of n as a sum of n squares of nonnegative integers.

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..500

FORMULA

a(n) = [x^n] (1 + theta_3(x))^n/2^n, where theta_() is the Jacobi theta function. - Ilya Gutkovskiy, Jan 17 2018

CROSSREFS

Cf. A045847.

Sequence in context: A203233 A112561 A303170 * A143567 A147375 A147216

Adjacent sequences:  A287614 A287615 A287616 * A287618 A287619 A287620

KEYWORD

nonn

AUTHOR

Seiichi Manyama, May 28 2017

STATUS

approved

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Last modified April 5 23:17 EDT 2020. Contains 333260 sequences. (Running on oeis4.)