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A117427 Triangle T, read by rows, equal to the matrix square of triangle A117418; also equals a column bisection of triangle A117418: column 2k+1 of T^(1/2) equals column k of T. 3
1, 2, 1, 4, 4, 1, 9, 14, 6, 1, 23, 50, 28, 8, 1, 66, 191, 126, 48, 10, 1, 209, 780, 572, 264, 70, 12, 1, 724, 3415, 2692, 1440, 438, 98, 14, 1, 2722, 15924, 13203, 7990, 2646, 698, 130, 16, 1, 11054, 78595, 67542, 45566, 15920, 4702, 1029, 168, 18, 1, 48221, 408337 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..56.

EXAMPLE

Triangle T begins:

1;

2, 1;

4, 4, 1;

9, 14, 6, 1;

23, 50, 28, 8, 1;

66, 191, 126, 48, 10, 1;

209, 780, 572, 264, 70, 12, 1;

724, 3415, 2692, 1440, 438, 98, 14, 1;

2722, 15924, 13203, 7990, 2646, 698, 130, 16, 1;

11054, 78595, 67542, 45566, 15920, 4702, 1029, 168, 18, 1; ...

The matrix square-root T^(1/2) = A117418, which begins:

1;

1, 1;

1, 2, 1;

1, 4, 3, 1;

1, 9, 8, 4, 1;

1, 23, 22, 14, 5, 1;

1, 66, 65, 50, 20, 6, 1;

1, 209, 208, 191, 79, 28, 7, 1; ...

where column 2k+1 of T^(1/2) equals column k of T for k>=0.

PROG

(PARI)

CROSSREFS

Cf. A117428 (row sums); A117418 (T^(1/2)), A117425 (dual).

Sequence in context: A263989 A202710 A200965 * A097761 A200756 A108556

Adjacent sequences:  A117424 A117425 A117426 * A117428 A117429 A117430

KEYWORD

nonn,tabl

AUTHOR

Paul D. Hanna, Mar 14 2006

STATUS

approved

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Last modified December 11 10:48 EST 2018. Contains 318049 sequences. (Running on oeis4.)