A058005 a(n) = gcd(2*n, binomial(2*n, n)).

2, 2, 2, 2, 2, 12, 2, 2, 2, 4, 2, 4, 2, 4, 30, 2, 2, 12, 2, 20, 6, 4, 2, 12, 2, 4, 2, 56, 2, 4, 2, 2, 6, 4, 14, 4, 2, 4, 2, 20, 2, 84, 2, 8, 90, 4, 2, 12, 2, 4, 6, 8, 2, 12, 2, 8, 6, 4, 2, 24, 2, 4, 6, 2, 10, 132, 2, 4, 6, 20, 2, 36, 2, 4, 30, 8, 154, 12, 2, 20, 2, 4, 2, 56, 10, 4, 6, 88, 2, 20

Offset

1,1

Comments

a(n)=2 for values like 1,2,3,4,5,7,...; a(n)=2n for values like 6,15,...,190.

Links

Table of n, a(n) for n=1..90.

Crossrefs

Cf. A001405, A071416.

Sequence in context: A216844 A088050 A260725 * A095386 A060359 A029665

Adjacent sequences: A058002 A058003 A058004 * A058006 A058007 A058008

Keyword

nonn

Author

Labos Elemer, Nov 13 2000

Extensions

Name corrected by Hugo Pfoertner, Mar 22 2020

Status

approved