A249431 a(n) = A249151(n) - n.

1, 0, 0, -2, 0, -3, 0, -6, -6, -5, 0, -4, 0, -7, -10, -14, 0, -15, 0, -15, -14, -11, 0, -12, -20, -13, -24, -21, 0, -4, 0, -30, -22, -17, -28, 1, 0, -19, -26, 1, 0, -35, 0, -33, -21, -23, 0, -28, -42, -45, -34, -39, 0, -51, -44, -20, -38, -29, 0, -12, 0, -31, 1, -62, -52, -55, 0, -51, -46, -20, 0, -30, 0

Offset

0,4

Comments

It seems that A006093 gives the positions of zeros.

Links

Chai Wah Wu, Table of n, a(n) for n = 0..10000 (terms 0..4096 from Antti Karttunen)

Formula

a(n) = A249151(n) - n.

Prog

(Scheme) (definec (A249431 n) (- (A249151 n) n))
(Python)
from itertools import count
from collections import Counter
from math import comb
from sympy import factorint
def A249431(n):
    p = sum((Counter(factorint(comb(n, i))) for i in range(n+1)), start=Counter())
    for m in count(1):
        f = Counter(factorint(m))
        if not f<=p:
            return m-1-n
        p -= f # Chai Wah Wu, Aug 19 2025

Crossrefs

A249433 and A249434 give the positions of negative and nonnegative values, respectively.

A249430 gives the position where +n appears for the first time, A249432 the positions of records of positive values.

Cf. A006093, A249151.

Sequence in context: A081155 A348075 A130628 * A331176 A076563 A163974

Adjacent sequences: A249428 A249429 A249430 * A249432 A249433 A249434

Keyword

sign

Author

Antti Karttunen, Nov 02 2014

Status

approved