A178855 Partial sums of A033485.

1, 3, 6, 11, 18, 28, 41, 59, 82, 112, 149, 196, 253, 323, 406, 507, 626, 768, 933, 1128, 1353, 1615, 1914, 2260, 2653, 3103, 3610, 4187, 4834, 5564, 6377, 7291, 8306, 9440, 10693, 12088, 13625, 15327, 17194, 19256, 21513, 23995, 26702, 29671, 32902, 36432

Offset

1,2

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Formula

a(n) = (A033485(2n+1)-1)/2.

Maple

b:= proc(n) option remember;
      `if`(n<2, n, b(n-1)+b(iquo(n, 2)))
    end:
a:= n-> (b(2*n+1)-1)/2:
seq(a(n), n=1..60);  # Alois P. Heinz, Feb 17 2022

Prog

(Python)
from itertools import islice
from collections import deque
def A178855_gen(): # generator of terms
    aqueue, f, b, a = deque([2]), True, 1, 2
    while True:
        a += b
        aqueue.append(a)
        if f:
            yield (a-1)//2
            b = aqueue.popleft()
        f = not f
A178885_list = list(islice(A178855_gen(), 40)) # Chai Wah Wu, Jun 08 2022

Crossrefs

Cf. A000123, A033485.

Sequence in context: A011849 A350104 A173690 * A095944 A014284 A118482

Adjacent sequences: A178852 A178853 A178854 * A178856 A178857 A178858

Keyword

nonn,easy

Author

Philippe Deléham, Jun 19 2010

Extensions

a(40) corrected by Georg Fischer, Aug 28 2020

Status

approved