

A334084


Integers m such that only 2 binomial coefficients C(m,k), with 0<=k<=m, are practical numbers.


2



1, 3, 5, 7, 15, 31, 63, 127, 255, 511, 1023
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OFFSET

1,2


COMMENTS

Integers m such that A334082(m) = m1.
Integers of the form 2^k1 with k>0 are terms, but this condition is not necessary since 5 is a term.


LINKS

Table of n, a(n) for n=1..11.


PROG

(PARI) isok(n) = sum(k=0, n, !is_A005153(binomial(n, k))) == n1;


CROSSREFS

Cf. A005153 (practical numbers), A007318 (binomial coefficients).
Cf. A334082, A334083.
Sequence in context: A261646 A303027 A217615 * A050553 A005540 A155802
Adjacent sequences: A334081 A334082 A334083 * A334085 A334086 A334087


KEYWORD

nonn,more


AUTHOR

Michel Marcus, Apr 14 2020


EXTENSIONS

a(11) from Jinyuan Wang, Apr 14 2020


STATUS

approved



