OFFSET
1,1
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
M. Alekseyev, PARI/GP Scripts for Miscellaneous Math Problems, sect. III: Binomial coefficients modulo integers, binomod.gp (V. 1.4, 11/2015).
FORMULA
a(n) = 2 * A014847(n). - Rémy Sigrist, Aug 27 2017
EXAMPLE
For n=30, binomial(30,15) = 155117520 = 15^10341168, so 30 is a term.
MAPLE
a:=[];
for n from 1 to 1000 do if ( binomial(2*n, n) mod n ) = 0 then a:=[op(a), 2*n]; fi; od;
a; # N. J. A. Sloane, Aug 03 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Definition corrected by N. J. A. Sloane, Aug 03 2017
STATUS
approved