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A028633 Expansion of (theta_3(z)*theta_3(17z) + theta_2(z)*theta_2(17z)). 1
1, 0, 2, 0, 0, 0, 0, 0, 2, 4, 0, 0, 0, 4, 0, 0, 0, 0, 2, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 2, 0, 4, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 4, 2, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 4, 0, 0, 2, 0, 0, 0, 0, 4, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Jinyuan Wang, Table of n, a(n) for n = 0..1000

MATHEMATICA

r[n_]:=Reduce[{x, y}.{{2, 1}, {1, 9}}.{x, y}==n, {x, y}, Integers]; Table[rn=r[n]; Which[rn===False, 0, Head[rn]===Or, Length[rn], Head[rn]===And, 1], {n, 0, 110}] (* Vincenzo Librandi, Feb 22 2020 *)

PROG

(PARI) a(n) = if(n<1, n==0, qfrep([2, 1; 1, 9], n)[n]*2); \\ Jinyuan Wang, Feb 21 2020

CROSSREFS

Cf. A028634, A028635, A028636.

Sequence in context: A216278 A133827 A176192 * A316898 A238429 A332671

Adjacent sequences:  A028630 A028631 A028632 * A028634 A028635 A028636

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified January 19 18:16 EST 2022. Contains 350466 sequences. (Running on oeis4.)