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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 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.)