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!)
 A257620 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) = 3*x + 3. 11

%I

%S 1,3,3,9,36,9,27,297,297,27,81,2106,5346,2106,81,243,13851,73386,

%T 73386,13851,243,729,87480,868239,1761264,868239,87480,729,2187,

%U 540189,9388791,34158753,34158753,9388791,540189,2187,6561,3293622,95843088,578903274,1024762590,578903274,95843088,3293622,6561

%N 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) = 3*x + 3.

%C Row sums are: 1, 6, 54, 648, 9720, 174960, 3674160, 88179840, 2380855680, 71425670400, 2357047123200, ... (see A034001).

%F 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) = 3*x + 3.

%e 1

%e 3 3

%e 9 36 9

%e 27 297 297 27

%e 81 2106 5346 2106 81

%e 243 13851 73386 73386 13851 243

%e 729 87480 868239 1761264 868239 87480 729

%e 2187 540189 9388791 34158753 34158753 9388791 540189 2187

%e 6561 3293622 95843088 578903274 1024762590 578903274 95843088 3293622 6561

%Y Cf. A142458, A257610, A257622, A257624, A257626.

%Y Cf. A038221, A257180, A257611, A257621, A257623, A257625, A257627.

%Y Similar sequences listed in A256890.

%K nonn,tabl

%O 0,2

%A _Dale Gerdemann_, May 09 2015

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 March 30 16:16 EDT 2020. Contains 333127 sequences. (Running on oeis4.)