A135885 Triangle Q, read by rows, where column k of Q equals column 0 of Q^(k+1) and Q is equal to the matrix square of integer triangle P = A135880 such that column 0 of Q equals column 0 of P shift left.

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, 86796, 101492, 39968, 8936, 1365, 156, 14, 1, 1049546, 1296934, 528306, 121532, 19090, 2250, 210, 16, 1, 14563135, 18868652, 7906598

Offset

0,2

Links

Table of n, a(n) for n=0..47.

Formula

See formulas relating triangles P, Q and R, in entry A135880.

Example

Triangle Q = P^2 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;
86796, 101492, 39968, 8936, 1365, 156, 14, 1;
1049546, 1296934, 528306, 121532, 19090, 2250, 210, 16, 1;
14563135, 18868652, 7906598, 1861416, 298830, 36028, 3451, 272, 18, 1;
228448504, 308478492, 132426050, 31785380, 5193982, 637390, 62230, 5016, 342, 20, 1; ...
where column k of Q equals column 0 of Q^(k+1) for k>=0.
Related triangle 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; ...
where column k of Q equals column 0 of P^(2k+2)
such that column 0 of P^2 equals column 0 of P shift left.
The matrix product P*R^-1*P = A135899 = Q (shifted down one row),
where 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; ...
in which column k of R equals column 0 of P^(2k+1).

Prog

(PARI) {T(n, k)=local(P=Mat(1), R, 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]))))); (P^2)[n+1, k+1]}

Crossrefs

Cf. columns: A135881, A135886, A135887; related tables: A135880 (P), A135894 (R), A135891 (Q^2), A135893 (Q^3); A135898 (P^-1*R), A135899 (P*R^-1*P), A135900 (R^-1*Q).

Sequence in context: A167560 A132159 A112356 * A162312 A141715 A329431

Adjacent sequences: A135882 A135883 A135884 * A135886 A135887 A135888

Keyword

nonn,tabl

Author

Paul D. Hanna, Dec 15 2007

Status

approved