A074364 Semi-tribonacci numbers, from tribonacci by analogy with semi-Fibonacci sequence.

0, 1, 1, 2, 1, 4, 2, 7, 1, 10, 4, 15, 2, 21, 7, 30, 1, 38, 10, 49, 4, 63, 15, 82, 2, 99, 21, 122, 7, 150, 30, 187, 1, 218, 38, 257, 10, 305, 49, 364, 4, 417, 63, 484, 15, 562, 82, 659, 2, 743, 99, 844, 21, 964, 122, 1107, 7, 1236, 150, 1393, 30, 1573, 187, 1790, 1, 1978, 218

Offset

0,4

Links

T. D. Noe, Table of n, a(n) for n = 0..10000

Cristina Ballantine and George Beck, Partitions enumerated by self-similar sequences, arXiv:2303.11493 [math.CO], 2023.

M. J. Halm, Sequences

Formula

a(0) = 0, a(1) = 1, a(2n) = a(n), a(2n+1) = a(2n)+a(2n-1)+a(2n-2)

Example

a(4)=1 because a(4/2)=a(2)=1.

Crossrefs

Cf. A030067, A000073.

Sequence in context: A334404 A143375 A339418 * A376318 A256610 A276055

Adjacent sequences: A074361 A074362 A074363 * A074365 A074366 A074367

Keyword

nonn

Author

Michael Joseph Halm, Feb 13 2003

Status

approved