A178334 Number of mountain numbers <= n.

0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset: 0

Author

Reinhard Zumkeller, May 25 2010

Keywords

• nonn

Comments

a(n) = 21846 for n >= 12345678987654321.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..20000

Crossrefs

Cf. A135417.

Programs

Python

from itertools import count, islice
def agen(): # generator of terms; uses code in A134941
    A134941_full = A134941() + [-1]
    c = i = 0
    for j in count(0):
        if j == A134941_full[i]: i, c = i+1, c+1
        yield c
print(list(islice(agen(), 122))) # Michael S. Branicky, Jan 09 2023

Formula

a(n) = Sum_{k=0..n} A178333(k).