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A136236 Matrix cube of triangle U = A136228, read by rows. 2
1, 3, 1, 21, 12, 1, 208, 156, 21, 1, 2637, 2350, 399, 30, 1, 40731, 41034, 8029, 750, 39, 1, 742620, 821562, 177198, 18865, 1209, 48, 1, 15624420, 18631332, 4317936, 502335, 36478, 1776, 57, 1, 372892266, 473187270, 115949841, 14390880, 1136811 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..40.

FORMULA

Column k of U^3 (this triangle) = column 2 of P^(3k+1), where P = triangle A136220.

EXAMPLE

This triangle, U^3, begins:

1;

3, 1;

21, 12, 1;

208, 156, 21, 1;

2637, 2350, 399, 30, 1;

40731, 41034, 8029, 750, 39, 1;

742620, 821562, 177198, 18865, 1209, 48, 1;

15624420, 18631332, 4317936, 502335, 36478, 1776, 57, 1;

372892266, 473187270, 115949841, 14390880, 1136811, 62488, 2451, 66, 1;

where column 0 of U^3 = column 2 of P = A136220.

PROG

(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^3)[n+1, k+1]}

CROSSREFS

Cf. A136223 (column 0); related tables: A136220 (P), A136228 (U), A136230 (V), A136231 (W=P^3), A136233 (U^2).

Sequence in context: A143173 A000369 A225471 * A113090 A223549 A138354

Adjacent sequences:  A136233 A136234 A136235 * A136237 A136238 A136239

KEYWORD

nonn,tabl

AUTHOR

Paul D. Hanna, Feb 07 2008

STATUS

approved

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Last modified May 25 12:30 EDT 2019. Contains 323568 sequences. (Running on oeis4.)