a(n) = Sum_{k=0..n} r_4(k^2 + 1), where r_4(k) is the number of ways of writing k as a sum of 4 squares (A000118).

A333174

a(n) = Sum_{k=0..n} r_4(k^2 + 1), where r_4(k) is the number of ways of writing k as a sum of 4 squares (A000118).

Terms

    a(0) =8a(1) =32a(2) =80a(3) =224a(4) =368a(5) =704a(6) =1008a(7) =1752a(8) =2424a(9) =3432a(10) =4248a(11) =5736a(12) =7176a(13) =9768a(14) =11352a(15) =14088a(16) =16152a(17) =20472a(18) =23944a(19) =28312a(20) =31528a(21) =37576a(22) =42280a(23) =50056a(24) =54680a(25) =62216a(26) =67640a(27) =78296a(28) =85880a(29) =96008

External references