|
Search: id:A109156
|
|
| |
|
| 1, 2, 5, 14, 47, 188, 867, 4460, 25025, 150890, 967825, 6554482, 46600855, 346228012, 2677951311, 21495038944, 178565654041, 1531692226714, 13538763090277, 123096619532030, 1149440819867767, 11007471611129700
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Triangular matrix T=A109152 satisfies: T(n,k) = [T^2](n-1,k) for n>k+1>=1, with T(n,n) = 1 and T(n+1,n) = n+1 for n>=0.
|
|
PROGRAM
|
(PARI) {a(n)=local(M=matrix(n+1, n+1)); M=M^0; for(i=1, n, M=matrix(n+1, n+1, r, c, if(r>=c, if(r==c, 1, if(r==c+1, c, (M^2)[r-1, c]))))); return(sum(k=0, n, M[n+1, k+1]))}
|
|
CROSSREFS
|
Cf. A109152 (triangle), A109153 (column 0), A109154 (column 1), A109155 (column 2).
Sequence in context: A115276 A096402 A007268 this_sequence A143918 A129867 A119841
Adjacent sequences: A109153 A109154 A109155 this_sequence A109157 A109158 A109159
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Paul D. Hanna (pauldhanna(AT)juno.com), Jun 20 2005
|
|
|
Search completed in 0.002 seconds
|
