0,4

This triangle U = P * [P^2 shift right one column] (see example), where P = A136220 and P^2 = A136225.

Triangle U begins:

1;

1, 1;

3, 4, 1;

15, 24, 7, 1;

108, 198, 63, 10, 1;

1036, 2116, 714, 120, 13, 1;

12569, 28052, 9884, 1725, 195, 16, 1;

185704, 446560, 162729, 29190, 3393, 288, 19, 1;

3247546, 8325700, 3117660, 571225, 67756, 5880, 399, 22, 1; ...

where column k of U = column 0 of P^(3k+1) and

triangle P = A136220 begins:

1;

1, 1;

3, 2, 1;

15, 10, 3, 1;

108, 75, 21, 4, 1;

1036, 753, 208, 36, 5, 1;

12569, 9534, 2637, 442, 55, 6, 1;

185704, 146353, 40731, 6742, 805, 78, 7, 1; ...

where column k of P = column 0 of U^(k+1).

Also, this triangle U can be obtained by the matrix product:

U = P * [P^2 shift right one column]

where P^2 shift right one column begins:

1;

0, 1;

0, 2, 1;

0, 8, 4, 1;

0, 49, 26, 6, 1;

0, 414, 232, 54, 8, 1;

0, 4529, 2657, 629, 92, 10, 1;

0, 61369, 37405, 9003, 1320, 140, 12, 1; ...

(PARI) {T(n, k)=local(P=Mat(1), U=Mat(1), PShR); if(n>0, for(i=0, n, PShR=matrix(#P, #P, r, c, if(r>=c, if(r==c, 1, if(c==1, 0, P[r-1, c-1])))); U=P*PShR^2; U=matrix(#P+1, #P+1, r, c, if(r>=c, if(r<#P+1, U[r, c], if(c==1, (P^3)[ #P, 1], (P^(3*c-1))[r-c+1, 1])))); P=matrix(#U, #U, r, c, if(r>=c, if(r<#R, P[r, c], (U^c)[r-c+1, 1]))))); U[n+1, k+1]}

Cf. A136221 (column 0), A136229 (column 1); related tables: A136220 (P), A136225 (P^2), A136230 (V), A136231 (W=P^3), A136217, A136218.

Adjacent sequences: A136225 A136226 A136227 this_sequence A136229 A136230 A136231

Sequence in context: A100326 A028338 A039757 this_sequence A055133 A113084 A055325

nonn,tabl

Paul D. Hanna (pauldhanna(AT)juno.com), Jan 28 2008