The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A257180 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) = x + 3. 9
 1, 3, 3, 9, 24, 9, 27, 141, 141, 27, 81, 726, 1410, 726, 81, 243, 3471, 11406, 11406, 3471, 243, 729, 15828, 81327, 136872, 81327, 15828, 729, 2187, 69873, 533259, 1390521, 1390521, 533259, 69873, 2187, 6561, 301362, 3295152, 12609198, 19467294, 12609198, 3295152, 301362, 6561, 19683, 1277619, 19489380, 105311556, 237144642, 237144642, 105311556, 19489380, 1277619, 19683 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Row sums are: 1, 6, 42, 336, 3024, 30240, 332640, 3991680, 51891840, 726485760, 10897286400, ... (see A001725). 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) = x + 3. EXAMPLE 1 3 3 9 24 9 27 141 141 27 81 726 1410 726 81 243 3471 11406 11406 3471 243 729 15828 81327 136872 81327 15828 729 2187 69873 533259 1390521 1390521 533259 69873 2187 6561 301362 3295152 12609198 19467294 12609198 3295152 301362 6561 PROG (PARI) f(x) = x + 3; T(n, k) = t(n-k, k); t(n, m) = {if (!n && !m, return(1)); if (n < 0 || m < 0, return (0)); f(m)*t(n-1, m) + f(n)*t(n, m-1); } tabl(nn) = {for (n=0, nn, for (k=0, n, print1(T(n, k), ", "); ); print(); ); } \\ Michel Marcus, Apr 23 2015 CROSSREFS Cf. A008292, A256890, A257606, A257607 Cf. A038221, A257611, A257620, A257621, A257623, A257625, A257627 Similar sequences listed in A256890. Sequence in context: A007683 A316220 A059728 * A184694 A215885 A176158 Adjacent sequences:  A257177 A257178 A257179 * A257181 A257182 A257183 KEYWORD nonn,tabl AUTHOR Dale Gerdemann, Apr 17 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 16 21:55 EDT 2021. Contains 345080 sequences. (Running on oeis4.)