login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A320188 Number of integer solutions to a^2 + 2*b^2 + 3*c^2 + 7*d^2 = n. 8
1, 2, 2, 6, 6, 4, 12, 6, 6, 18, 12, 20, 26, 28, 20, 20, 34, 4, 30, 44, 20, 48, 44, 20, 20, 38, 16, 42, 62, 40, 56, 48, 34, 24, 72, 40, 70, 112, 36, 56, 68, 44, 40, 124, 60, 60, 124, 24, 66, 62, 54, 96, 92, 80, 64, 80, 64, 88, 136, 64, 76, 140, 52, 70, 166, 44, 104, 196, 44 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
a(n) > 0 for n >= 0.
LINKS
FORMULA
G.f.: theta_3(q) * theta_3(q^2) * theta_3(q^3) * theta_3(q^7).
MATHEMATICA
CoefficientList[Series[Product[EllipticTheta[3, 0, q^k], {k, 1, 3}]*EllipticTheta[3, 0, q^7], {q, 0, 80}], q] (* G. C. Greubel, Oct 29 2018 *)
PROG
(PARI) q='q+O('q^80); Vec(prod(k=1, 3, eta(q^(2*k))^5/(eta(q^k)* eta(q^(4*k)))^2 )*eta(q^(14))^5/(eta(q^7)* eta(q^(28)))^2 ) \\ G. C. Greubel, Oct 29 2018
CROSSREFS
Sequence in context: A320191 A320190 A320189 * A033712 A033730 A033754
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 07 2018
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 21 16:49 EDT 2024. Contains 371874 sequences. (Running on oeis4.)