A279948 Expansion of (Sum_{k>=1} x^(prime(k)^2))^3.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 3, 0, 0, 0, 0, 3, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 6, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 3, 0, 3, 0, 0, 6, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 6, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3

Offset: 0

Author

Ilya Gutkovskiy, Dec 24 2016

Keywords

• nonn

Comments

Number of ordered ways of writing n as the sum of three squares of primes (A001248).

Examples

			a(22) = 3 because we have [4, 9, 9], [9, 4, 9] and [9, 9, 4].
		

Links

• Index entries for sequences related to sums of squares

Crossrefs

Cf. A001248, A063691, A098238.

Programs

Mathematica

nmax = 125; CoefficientList[Series[(Sum[x^Prime[k]^2, {k, 1, nmax}])^3, {x, 0, nmax}], x]

Formula

G.f.: (Sum_{k>=1} x^(prime(k)^2))^3.