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A333173
a(n) = r_4(n^2 + 1), where r_4(k) is the number of ways of writing k as a sum of 4 squares (A000118).
2
8, 24, 48, 144, 144, 336, 304, 744, 672, 1008, 816, 1488, 1440, 2592, 1584, 2736, 2064, 4320, 3472, 4368, 3216, 6048, 4704, 7776, 4624, 7536, 5424, 10656, 7584, 10128, 7776, 12768, 10416, 15840, 10080, 14736, 10384, 19872, 14736, 18288, 12816, 20904, 16992, 28272
OFFSET
0,1
LINKS
R. Sitaramachandrarao and P. V. Krishnaiah, On the sums Sigma_{n<=x} A(f(n)) and Sigma_{p<=x} A(f(p)), Journal of Number Theory, Vol. 23, No. 2 (1986), pp. 149-168.
FORMULA
a(n) = A000118(A002522(n)).
EXAMPLE
a(0) = r_4(0^2 + 1) = r_4(1) = A000118(1) = 8.
MATHEMATICA
Table[SquaresR[4, k^2 + 1], {k, 0, 100}]
KEYWORD
nonn
AUTHOR
Amiram Eldar, Mar 09 2020
STATUS
approved