This site is supported by donations to The OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A099944 Number of 3 X n binary matrices avoiding simultaneously the right angled numbered polyomino patterns (ranpp) (00;1) and (11;0). 0
 76, 164, 340, 692, 1396, 2804, 5620, 11252, 22516, 45044, 90100, 180212, 360436, 720884, 1441780, 2883572, 5767156, 11534324, 23068660, 46137332, 92274676, 184549364, 369098740, 738197492, 1476394996, 2952790004, 5905580020 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,1 COMMENTS 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 i10 and n>2; for n=2 the number is (m+1)*2^m. LINKS 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 (3,-2). FORMULA a(n) = 11*2^n - 12. From Chai Wah Wu, Jun 06 2016: (Start) a(n) = 3*a(n-1) - 2*a(n-2) for n > 4. G.f.: 4*x^3*(19 - 16*x)/((1 - x)*(1 - 2*x)). (End) MATHEMATICA LinearRecurrence[{3, -2}, {76, 164}, 30] (* Harvey P. Dale, Oct 22 2017 *) PROG (PARI) vector(50, n, i=n+2; 11*2^i - 12) \\ Michel Marcus, Dec 01 2014 CROSSREFS Cf. A000105. Sequence in context: A063359 A044327 A044708 * A044408 A044789 A245005 Adjacent sequences:  A099941 A099942 A099943 * A099945 A099946 A099947 KEYWORD nonn,easy AUTHOR Sergey Kitaev, Nov 12 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 18 14:11 EDT 2019. Contains 328161 sequences. (Running on oeis4.)