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

0,4

Links

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

Formula

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

Example

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

Prog

(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

Crossrefs

Cf. A000213.

Sequence in context: A079428 A094548 A112661 * A254689 A176445 A292863

Adjacent sequences: A230722 A230723 A230724 * A230726 A230727 A230728

Keyword

nonn,base

Author

Irene Sermon, Oct 28 2013

Status

approved