A062561 a(n) = 3*binomial(2*n, n-1).

0, 3, 12, 45, 168, 630, 2376, 9009, 34320, 131274, 503880, 1939938, 7488432, 28973100, 112326480, 436268025, 1697168160, 6611884290, 25792489800, 100734001830, 393847225200, 1541374822260, 6037849200240, 23671113341850

Offset

0,2

Comments

a(n) equals 2^(3+2n) times the coefficient of Pi in 2F1(1/2, n+2, 5/2, -1). - John M. Campbell, Jul 17 2011

The array view of A029635 is

2, 2, 2, 2, 2, 2, ...

1, 3, 5, 7, 9, 11, ...

1, 4, 9, 16, 25, 36, ...

1, 5, 14, 30, 55, 91, ...

1, 6, 20, 50, 105, 196, ...

1, 7, 27, 77, 182, 378, ...

and a(n) is the incomplete hook sum Sum_{k=0..n-1} A(n,k) + Sum_{r=0..n-1} A(r,n). - R. J. Mathar, Jun 30 2013

Links

Harry J. Smith, Table of n, a(n) for n = 0..200

Mathematica

Table[3*Binomial[2*n, n-1], {n, 0, 25}]

Prog

(PARI) for(n=0, 22, print(3*binomial(2*n, n-1)))
(PARI) { for (n=0, 200, write("b062561.txt", n, " ", 3*binomial(2*n, n - 1)) ) } \\ Harry J. Smith, Aug 08 2009
(Magma) [3*n*Catalan(n): n in [0..30]]; // Vincenzo Librandi, Jul 19 2011

Crossrefs

Cf. A001791.

Sequence in context: A258626 A064017 A005320 * A128593 A359813 A085481

Adjacent sequences: A062558 A062559 A062560 * A062562 A062563 A062564

Keyword

easy,nonn

Author

Jason Earls, Jul 13 2001

Status

approved