A230724 Digital sum of tribonacci numbers with a(0)=a(1)=0, a(2)=1.

0, 0, 1, 1, 2, 4, 7, 4, 6, 8, 9, 14, 13, 9, 18, 13, 13, 26, 16, 19, 25, 15, 14, 18, 20, 34, 36, 36, 25, 34, 32, 37, 40, 46, 42, 47, 45, 35, 37, 36, 45, 37, 55, 47, 58, 43, 49, 42, 62, 63, 41, 58, 45, 63, 67, 76, 71, 43, 73, 70, 60, 86, 63, 83, 61, 72, 99, 88, 61

Offset: 0

Author

Irene Sermon, Oct 28 2013

Keywords

• nonn
• base

Examples

			In the tribonacci series with initial terms a(0)=a(1)=0 and a(2)=1, the 30th term is 15902591. Its digital sum is 32.
		

Links

• Irene Sermon, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000073.

Programs

Mathematica

t = LinearRecurrence[{1, 1, 1}, {0, 0, 1}, 60]; Total /@ IntegerDigits /@ t (* T. D. Noe, Oct 30 2013 *)

Formula

a(n) = A007953(A000073(n)).