A004160 Sum of digits of the n-th tetrahedral number.

1, 4, 1, 2, 8, 11, 12, 3, 12, 4, 16, 13, 14, 11, 14, 15, 24, 6, 7, 10, 16, 8, 5, 8, 18, 18, 18, 10, 22, 19, 20, 26, 20, 12, 21, 21, 22, 25, 13, 14, 11, 14, 15, 15, 15, 25, 19, 16, 17, 5, 17, 18, 18, 18, 19, 22, 19, 11, 26, 20, 21, 21, 21, 22, 25, 13, 23, 20, 23, 24, 24, 24, 25, 10, 16, 26

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000292, A007953.

Programs

Mathematica

Total[IntegerDigits[#]]&/@Table[(n(n+1)(n+2))/6,{n,80}] (* Harvey P. Dale, Jul 31 2013 *)

PARI

a(n)=sumdigits(n*(n+1)*(n+2)/6) \\ Charles R Greathouse IV, Dec 19 2016

Formula

a(n) = A007953(A000292(n)). - Michel Marcus, Dec 19 2016