A152670 Even Catalan numbers.

2, 14, 42, 132, 1430, 4862, 16796, 58786, 208012, 742900, 2674440, 35357670, 129644790, 477638700, 1767263190, 6564120420, 24466267020, 91482563640, 343059613650, 1289904147324, 4861946401452, 18367353072152, 69533550916004

Offset: 1

Author

Omar E. Pol, Dec 10 2008

Keywords

• easy
• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..541 [duplicated terms at n=343 and n=393 removed by _Georg Fischer_, Oct 19 2024]

Crossrefs

Cf. A000108, A038003, A152671.

Programs

Mathematica

Select[CatalanNumber[Range[30]], EvenQ] (* Vladimir Reshetnikov, Nov 02 2015 *)

PARI

lista(nn) = for (n=1, nn, if (((c=binomial(2*n,n)/(n+1)) % 2) == 0, print1(c, ", "))); \\ Michel Marcus, Nov 02 2015