A135900 Triangle, read by rows equal to the matrix product R^-1*Q, where Q = A135885 and R = A135894; R^-1*Q equals triangle R shifted down one row.

1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 6, 12, 5, 1, 1, 25, 63, 30, 7, 1, 1, 138, 421, 220, 56, 9, 1, 1, 970, 3472, 1945, 525, 90, 11, 1, 1, 8390, 34380, 20340, 5733, 1026, 132, 13, 1, 1, 86796, 399463, 247066, 72030, 13305, 1771, 182, 15, 1, 1, 1049546, 5344770, 3430936

Offset

0,7

Links

Table of n, a(n) for n=0..57.

Example

Triangle begins:
1;
1, 1;
1, 1, 1;
2, 3, 1, 1;
6, 12, 5, 1, 1;
25, 63, 30, 7, 1, 1;
138, 421, 220, 56, 9, 1, 1;
970, 3472, 1945, 525, 90, 11, 1, 1;
8390, 34380, 20340, 5733, 1026, 132, 13, 1, 1;
86796, 399463, 247066, 72030, 13305, 1771, 182, 15, 1, 1; ...
This triangle equals matrix product R^-1*Q,
which equals triangle R shifted down one row,
where P = A135880 begins:
1;
1, 1;
2, 2, 1;
6, 7, 3, 1;
25, 34, 15, 4, 1;
138, 215, 99, 26, 5, 1;
970, 1698, 814, 216, 40, 6, 1; ...
and Q = P^2 = A135885 begins:
1;
2, 1;
6, 4, 1;
25, 20, 6, 1;
138, 126, 42, 8, 1;
970, 980, 351, 72, 10, 1;
8390, 9186, 3470, 748, 110, 12, 1; ...
and R = A135894 begins:
1;
1, 1;
2, 3, 1;
6, 12, 5, 1;
25, 63, 30, 7, 1;
138, 421, 220, 56, 9, 1;
970, 3472, 1945, 525, 90, 11, 1; ...
where column k of R equals column 0 of P^(2k+1),
and column k of Q=P^2 equals column 0 of P^(2k+2), for k>=0.

Prog

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

Crossrefs

Cf. A135880 (P), A135885 (Q=P^2), A135894 (R); A135898 (P^-1*R), A135899 (P*R^-1*P).

Sequence in context: A308290 A204167 A217897 * A338072 A173272 A326303

Adjacent sequences: A135897 A135898 A135899 * A135901 A135902 A135903

Keyword

nonn,tabl

Author

Paul D. Hanna, Dec 15 2007

Status

approved