A109125 Column 7 of array illustrated in A089574 and related to A034261.

2, 41, 292, 1283, 4253, 11712, 28261, 61738, 124763, 236762, 426557, 735616, 1222064, 1965563, 3073176, 4686337, 6989056, 10217495, 14671058, 20725145, 28845727, 39605906, 53704631, 71987748, 95471569, 125369152, 163119491

Offset

0,1

Links

Table of n, a(n) for n=0..26.

Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1). [From R. J. Mathar, Jun 26 2010]

Formula

From R. J. Mathar, Jun 26 2010: (Start)

a(n) = A105552(11+n,5+n).

G.f.: x*(-2-23*x+5*x^2+37*x^3-26*x^4-9*x^5+17*x^6-7*x^7+x^8)/(x-1)^9. a(n) = -1+1277*n/840 -19*n^3/480 -67*n^2/480 +41*n^5/80 +257*n^6/2800 +23*n^7/3360 +6049*n^4/5760 +n^8/5760. (End)

Example

a(1) = 2 because 4+4+4 and 3+3+3+3 cannot be permuted. a(2) = 41 because there are 3 + 7 + 12 + 9 + 10 ways of permuting the associated partitions.
5553 (3 ways), 4441 & 544 (4+3 ways), 4432 (12 ways), 33331 & 4333 (5 + 4 ways) and 33322 (in 10 ways).

Crossrefs

Cf. A000124, A000330, A034261, A086602, A089574, A107601.

Sequence in context: A063271 A142160 A174615 * A037061 A065587 A264453

Adjacent sequences: A109122 A109123 A109124 * A109126 A109127 A109128

Keyword

easy,nonn

Author

Alford Arnold, Jun 19 2005

Extensions

Extended beyond a(6) by R. J. Mathar, Jun 26 2010

Status

approved