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!)
A279372 Expansion of (Sum_{k>=1} x^(prime(k)^2))^2. 0
0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,14
COMMENTS
Number of ordered ways of writing n as the sum of two squares of primes (A001248).
LINKS
FORMULA
G.f.: (Sum_{k>=1} x^(prime(k)^2))^2.
a(n) = Sum_{i=1..n} A302048(i)*A302048(n-i). - Ridouane Oudra, Nov 21 2020
EXAMPLE
a(13) = 2 because we have [4, 9] and [9, 4].
MATHEMATICA
nmax = 125; CoefficientList[Series[(Sum[x^Prime[k]^2, {k, 1, nmax}])^2, {x, 0, nmax}], x]
CROSSREFS
Sequence in context: A230686 A341001 A221836 * A086077 A178408 A073345
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Dec 24 2016
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 March 28 17:42 EDT 2024. Contains 371254 sequences. (Running on oeis4.)