1,3

Table of n, a(n) for n=1..75.

Paolo Leonetti, Carlo Sanna, Practical numbers among the binomial coefficients, arXiv:1905.12023 [math.NT], 2019.

(PARI) a(n) = sum(k=0, n, !is_A005153(binomial(n, k)));

Cf. A005153 (practical numbers), A007318 (binomial coefficients).

Cf. A334083, A334084.

Sequence in context: A153733 A083218 A203908 * A307704 A139716 A168232

Adjacent sequences: A334079 A334080 A334081 * A334083 A334084 A334085

nonn

Michel Marcus, Apr 14 2020

approved