A230725 Digital sum of tribonacci numbers with a(0)=a(1)=a(2)=1.

1, 1, 1, 3, 5, 9, 8, 4, 12, 6, 13, 13, 14, 4, 13, 13, 21, 20, 18, 32, 25, 21, 33, 25, 43, 20, 16, 25, 16, 21, 53, 36, 38, 46, 48, 51, 46, 64, 44, 55, 46, 46, 48, 41, 45, 53, 58, 57, 60, 49, 58, 59, 67, 58, 76, 57, 65, 72, 77, 61

Offset: 0

Author

Irene Sermon, Oct 28 2013

Keywords

• nonn
• base

Examples

			In the tribonacci sequence with initial values a(0)=a(1)=a(2)=1, the 30th term is 37895489. Its digital sum is 53.
		

Links

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

Crossrefs

Cf. A000213.

Programs

Mathematica

Total[IntegerDigits[#]]&/@LinearRecurrence[{1,1,1},{1,1,1},60] (* Harvey P. Dale, Mar 18 2025 *)

Sage

L=[1,1,1]
n=100 #change for more terms
for i in [3..n]:
    L.append(L[i-3]+L[i-2]+L[i-1])
[sum(x.digits(base=10)) for x in L] # Tom Edgar, Nov 09 2013

Formula

a(n) = A007953(A000213(n)).