A226506 a(n) = B(n+2)-3*B(n+1)+B(n), where B(i) are the Bell numbers A000110.

0, 0, 2, 12, 62, 320, 1712, 9604, 56674, 351792, 2293862, 15682216, 112179608, 837905016, 6522165834, 52807401908, 443962338894, 3869376656384, 34908008426360, 325530083655692, 3133830448212442, 31106728455899128, 318009567467999574, 3344865730200667832, 36161434396223563504

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

B. Chern, P. Diaconis, D. M. Kane, and R. C. Rhoades, Closed expressions for averages of set partition statistics, arXiv:1304.4309 [math.CO], 2013.

Mathematica

Table[BellB[n+2] - 3 BellB[n+1] + BellB[n], {n, 0, 30}] (* Vincenzo Librandi, Jul 16 2013 *)
#[[3]]-3#[[2]]+#[[1]]&/@Partition[BellB[Range[0, 30]], 3, 1] (* Harvey P. Dale, Aug 26 2021 *)

Prog

(Magma) [Bell(n+2)-3*Bell(n+1)+Bell(n): n in [0..30]]; // Vincenzo Librandi, Jul 16 2013

Crossrefs

Cf. A000110.

Cf. A005493, A225591 (see Prop 3.1 (i) in Chern et al. link).

Sequence in context: A121177 A125831 A289787 * A026076 A361812 A231025

Adjacent sequences: A226503 A226504 A226505 * A226507 A226508 A226509

Keyword

nonn

Author

N. J. A. Sloane, Jun 10 2013

Status

approved