This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A109318 Column 2 of triangle T=A109316 where T(n,k) = [T^2](n-1,k) + [T^2](n-2,k-1) and T^2 is the matrix square of A109316. 3
 1, 2, 8, 36, 176, 920, 5080, 29336, 175752, 1085496, 6877240, 44518520, 293513784, 1965904984, 13348449784, 91723622936, 636923476728, 4463989946072, 31545992160568, 224580029779608, 1609455072125816, 11603437881340888 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS PROG (PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+3, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, if(i==2, B[i, j]=1, B[i, j]=(A^2)[i-1, j]+if(j>1, (A^2)[i-2, j-1]))); )); A=B); return(A[n+3, 3])} CROSSREFS Cf. A109316 (triangle), A109317 (column 0), A109319 (row sums), A000108. Sequence in context: A190862 A110837 A166229 * A113327 A227791 A245102 Adjacent sequences:  A109315 A109316 A109317 * A109319 A109320 A109321 KEYWORD nonn AUTHOR Paul D. Hanna, Jul 07 2005 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 16 08:50 EDT 2019. Contains 328056 sequences. (Running on oeis4.)