OFFSET

1,1

COMMENTS

If a term k > 2 is divisible by a prime p, then all digits in the base-p expansion of k are less than p/2. In particular, 2 is the only even term. - Robert Israel, Aug 02 2019

LINKS

Juri-Stepan Gerasimov and others, C(2n,n) - n^2 and C(n^2,n) - n^n, SeqFan list, April 20, 2018.

MAPLE

filter:= t -> isprime(binomial(2*t, t)-t^2):

select(filter, [2, seq(i, i=3..6000, 2)]); # Robert Israel, Aug 02 2019

PROG

(PARI) is(n)=ispseudoprime(binomial(2*n, n)-n^2)

for(n=0, oo, is(n) && print1(n, ", "))

CROSSREFS

KEYWORD

nonn,hard,more

AUTHOR

M. F. Hasler (at the suggestion of Juri-Stepan Gerasimov and others), Jul 21 2019

EXTENSIONS

a(15)-a(16) from Michael S. Branicky, Aug 24 2024

STATUS

approved