A048204 a(n) = T(n+1,n), array T given by A048201.

2, 6, 11, 19, 29, 43, 58, 74, 95, 117, 142, 168, 196, 229, 263, 298, 334, 372, 412, 454, 500, 548, 597, 647, 700, 757, 817, 879, 943, 1008, 1078, 1155, 1235, 1316, 1399, 1484, 1570, 1660, 1751, 1843, 1943, 2047, 2154, 2262, 2378, 2497, 2621, 2748, 2880, 3013

Offset

1,1

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Formula

a(n) = A004978(n+2) - 2. - Sean A. Irvine, Jun 05 2021

Prog

(Python)
from itertools import count, accumulate, islice
from collections import deque
def A048204_gen(): # generator of terms
    aset, alist, c = {1}, deque([1]), 0
    for k in count(2):
        if k in aset:
            aset.remove(k)
        else:
            yield (c:=c+k)
            aset |= set(k+d for d in accumulate(alist))
            alist.appendleft(k)
A048204_list = list(islice(A048204_gen(), 50)) # Chai Wah Wu, Sep 01 2025

Crossrefs

Cf. A004978, A048201.

Sequence in context: A194455 A163324 A317186 * A259411 A058760 A239071

Adjacent sequences: A048201 A048202 A048203 * A048205 A048206 A048207

Keyword

nonn

Author

Clark Kimberling

Status

approved