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A017293 a(n) = 10n+2. 21
2, 12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142, 152, 162, 172, 182, 192, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 302, 312, 322, 332, 342, 352, 362, 372, 382, 392, 402, 412, 422, 432, 442, 452, 462, 472, 482, 492, 502, 512, 522, 532 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Number of 5 X n 0-1 matrices avoiding simultaneously the right angled numbered polyomino patterns (ranpp) (00;1), (01;0), (11;0) and (01;1). An occurrence of a ranpp (xy;z) in a matrix A=(a(i,j)) is a triple (a(i1,j1), a(i1,j2), a(i2,j1)) where i1<i2, j1<j2 and these elements are in the same relative order as those in the triple (x,y,z). In general, the number of m x n 0-1 matrices in question is given by 2^m+2m(n-1). Cf. m=2: A008574; m=3: A016933; m=4: A022144; m=6: A017569. - Sergey Kitaev (kitaev(AT)ms.uky.edu), Nov 13 2004

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..5000

Tanya Khovanova, Recursive Sequences

S. Kitaev, On multi-avoidance of right angled numbered polyomino patterns, Integers: Electronic Journal of Combinatorial Number Theory 4 (2004), A21, 20pp.

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

FORMULA

a(n) = 2 * A016861(n) = A008592(n) + 2. - Wesley Ivan Hurt, May 03 2014

G.f.: 2*(1 + 4*x)/(1-x)^2. - Vincenzo Librandi, Jul 23 2016

MAPLE

A017293:=n->10*n+2; seq(A017293(n), n=0..100); # Wesley Ivan Hurt, May 03 2014

MATHEMATICA

Range[2, 1000, 10] (* Vladimir Joseph Stephan Orlovsky, May 28 2011 *)

CoefficientList[Series[(2 + 8 x) / (1 - x)^2, {x, 0, 30}], x] (* Vincenzo Librandi, Jul 23 2016 *)

PROG

(MAGMA) [10*n+2: n in [0..50]]; // Vincenzo Librandi, May 04 2011

CROSSREFS

Subsequence of A034709, together with A017281, A139222, A139245, A017329, A139249, A139264, A139279 and A139280.

Sequence in context: A191226 A063599 A163479 * A244188 A189330 A120672

Adjacent sequences:  A017290 A017291 A017292 * A017294 A017295 A017296

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Dec 11 1996

STATUS

approved

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Last modified May 28 04:27 EDT 2017. Contains 287212 sequences.