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!)
 A084608 Triangle, read by rows, where the n-th row lists the (2n+1) coefficients of (1+2x+3x^2)^n. 6
 1, 1, 2, 3, 1, 4, 10, 12, 9, 1, 6, 21, 44, 63, 54, 27, 1, 8, 36, 104, 214, 312, 324, 216, 81, 1, 10, 55, 200, 530, 1052, 1590, 1800, 1485, 810, 243, 1, 12, 78, 340, 1095, 2712, 5284, 8136, 9855, 9180, 6318, 2916, 729, 1, 14, 105, 532, 2009, 5922, 13993, 26840, 41979 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Alois P. Heinz, Rows n = 0..100, flattened EXAMPLE Triangle begins: 1, 1,  2,  3, 1,  4, 10,  12,   9, 1,  6, 21,  44,  63,   54,   27, 1,  8, 36, 104, 214,  312,  324,  216,   81, 1, 10, 55, 200, 530, 1052, 1590, 1800, 1485, 810, 243, MAPLE f:= proc(n) option remember; expand((1+2*x+3*x^2)^n) end: T:= (n, k)-> coeff(f(n), x, k): seq(seq(T(n, k), k=0..2*n), n=0..10);  # Alois P. Heinz, Apr 03 2011 MATHEMATICA row[n_] := (1+2x+3x^2)^n + O[x]^(2n+1) // CoefficientList[#, x]&; Table[row[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Feb 01 2017 *) PROG (PARI) for(n=0, 10, for(k=0, 2*n, t=polcoeff((1+2*x+3*x^2)^n, k, x); print1(t", ")); print(" ")) (Haskell) a084608 n = a084608_list !! n a084608_list = concat \$ iterate ([1, 2, 3] *) [1] instance Num a => Num [a] where    fromInteger k = [fromInteger k]    (p:ps) + (q:qs) = p + q : ps + qs    ps + qs         = ps ++ qs    (p:ps) * qs'@(q:qs) = p * q : ps * qs' + [p] * qs    _ * _               = [] -- Reinhard Zumkeller, Apr 02 2011 CROSSREFS Cf. A002426, A084600-A084606, A006139, A084609-A084615. Sequence in context: A076732 A130152 A211233 * A078990 A176566 A079639 Adjacent sequences:  A084605 A084606 A084607 * A084609 A084610 A084611 KEYWORD nonn,tabf AUTHOR Paul D. Hanna, Jun 01 2003 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 July 24 05:23 EDT 2021. Contains 346273 sequences. (Running on oeis4.)