A069306 Number of 2 X n binary arrays with a path of adjacent 1's from upper left corner to anywhere in right hand column.

5, 12, 29, 70, 169, 408, 985, 2378, 5741, 13860, 33461, 80782, 195025, 470832, 1136689, 2744210, 6625109, 15994428, 38613965, 93222358, 225058681, 543339720, 1311738121, 3166815962, 7645370045, 18457556052, 44560482149, 107578520350, 259717522849, 627013566048, 1513744654945, 3654502875938

Offset

2,1

Links

Indranil Ghosh, Table of n, a(n) for n = 2..2607

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (2,1).

Formula

G.f.: x^2(2x+5)/(1-2x-x^2). a(n) = A000129(n+1), as proved by Tomislav Doslic. - Ralf Stephan, Nov 16 2004

a(n) = 2*a(n-1)+a(n-2). [Philippe Deléham, Nov 20 2008]

Crossrefs

Cf. A069307 (3 X n), A069308 (4 X n), A069309 (5 X n), A069310 (6 X n), A069311 (7 X n), A069312 (8 X n), A069313 (9 X n), A069314 (10 X n), A069315 (11 X n), A069316 (12 X n), A069317 (13 X n), A069318 (14 X n), A069319 (15 X n), A069320 (16 X n).

Cf. A069294-A069305 (by columns).

Cf. A000129, A048624, A077985.

Sequence in context: A000465 A283506 A266471 * A277088 A009412 A009428

Adjacent sequences: A069303 A069304 A069305 * A069307 A069308 A069309

Keyword

nonn,easy

Author

R. H. Hardin, Mar 14 2002

Status

approved