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A257625 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 6*x + 3. 9
1, 3, 3, 9, 54, 9, 27, 621, 621, 27, 81, 6156, 18630, 6156, 81, 243, 57591, 408726, 408726, 57591, 243, 729, 526338, 7685847, 17166492, 7685847, 526338, 729, 2187, 4765473, 132656859, 568014201, 568014201, 132656859, 4765473, 2187 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums are: 1, 6, 72, 1296, 31104, 933120, 33592320, 1410877440, 67722117120, 3656994324480, ... (see A047058).

LINKS

Table of n, a(n) for n=0..35.

FORMULA

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 6*x + 3.

EXAMPLE

1

3 3

9 54 9

27 621 621 27

81 6156 18630 6156 81

243 57591 408726 408726 57591 243

729 526338 7685847 17166492 7685847 526338 729

2187 4765473 132656859 568014201 568014201 132656859 4765473 2187

CROSSREFS

Cf. A142461, A257616.

Cf. A038221, A257180, A257611, A257620, A257621, A257623, A257625, A257627.

See similar sequences listed in A256890.

Sequence in context: A257621 A190960 A257623 * A216147 A257627 A115564

Adjacent sequences:  A257622 A257623 A257624 * A257626 A257627 A257628

KEYWORD

nonn,tabl

AUTHOR

Dale Gerdemann, May 10 2015

STATUS

approved

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Last modified April 10 02:39 EDT 2020. Contains 333392 sequences. (Running on oeis4.)