A215449 Duplicate of A259967.
5, 10, 17, 29, 51, 90
Offset: 3
This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a259968 n = a259968_list !! n a259968_list = 1 : 1 : 3 : 6 : zipWith3 (((+) .) . (+)) a259968_list (drop 2 a259968_list) (drop 3 a259968_list) -- Reinhard Zumkeller, Jul 12 2015
I:=[1,1,3,6]; [n le 4 select I[n] else Self(n-1)+Self(n-2)+Self(n-4): n in [1..40]]; // Vincenzo Librandi, Jul 12 2015
LinearRecurrence[{1, 1, 0, 1}, {1, 1, 3, 6}, 40] (* Vincenzo Librandi, Jul 12 2015 *)
nxt[{a_,b_,c_,d_}]:={b,c,d,a+c+d}; NestList[nxt,{1,1,3,6},40][[;;,1]] (* Harvey P. Dale, Jan 28 2025 *)
Vec(-x*(2*x^2-x+1)/(x^3-x^2+2*x-1) + O(x^50)) \\ Colin Barker, Jul 12 2015
a259967 n = a259967_list !! n a259967_list = 3 : 2 : 2 : 5 : zipWith3 (((+) .) . (+)) a259967_list (drop 2 a259967_list) (drop 3 a259967_list) -- Reinhard Zumkeller, Jul 12 2015
concat(0, Vec(x*(x^4-6*x^3+7*x^2-2*x+1)/(x^3-x^2+2*x-1)^2 + O(x^40))) \\ Colin Barker, Jul 12 2015
Square array begins: 1, 2, 3, 4, 5, 6, 7, 8, 9, ... 1, 1, 2, 3, 4, 5, 6, 7, 8, ... 1, 3, 2, 3, 4, 5, 6, 7, 8, ... 1, 4, 5, 3, 4, 5, 6, 7, 8, ... 1, 7, 10, 7, 4, 5, 6, 7, 8, ... 1, 11, 17, 18, 9, 5, 6, 7, 8, ... 1, 18, 29, 39, 28, 11, 6, 7, 8, ... 1, 29, 51, 73, 74, 40, 13, 7, 8, ... 1, 47, 90, 127, 164, 125, 54, 15, 8, ...