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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A103780 Row sums of square of trinomial triangle A071675. 1
1, 1, 3, 9, 25, 69, 189, 519, 1428, 3930, 10812, 29742, 81816, 225070, 619156, 1703262, 4685565, 12889687, 35458707, 97544655, 268339161, 738183999, 2030697309, 5586319365, 15367609920, 42275319276, 116296719448 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (1,2,4,6,8,8,6,3,1).

FORMULA

G.f.: 1/(1-x-2*x^2-4*x^3-6*x^4-8*x^5-8*x^6-6*x^7-3*x^8-x^9).

a(n) = a(n-1) +2a(n-2) +4a(n-3) +6a(n-4) +8a(n-5) +8a(n-6) +6a(n-7) +3a(n-8) +a(n-9).

MATHEMATICA

CoefficientList[Series[1/(1 - x - 2*x^2 - 4*x^3 - 6*x^4 - 8*x^5 - 8*x^6 - 6*x^7 - 3*x^8 - x^9), {x, 0, 50}], x] (* G. C. Greubel, Mar 03 2017 *)

LinearRecurrence[{1, 2, 4, 6, 8, 8, 6, 3, 1}, {1, 1, 3, 9, 25, 69, 189, 519, 1428}, 40] (* Harvey P. Dale, Jun 14 2020 *)

PROG

(Maxima)

a(n):=sum(sum((sum(binomial(j, n-3*k+2*j)*(-1)^(j-k)*binomial(k, j), j, 0, k)) *sum(binomial(j, -3*m+k+2*j)*binomial(m, j), j, 0, m), k, m, n), m, 0, n); /* Vladimir Kruchinin, Dec 01 2011 */

(PARI) x='x+O('x^50); Vec(1/(1 -x -2*x^2 -4*x^3 -6*x^4 -8*x^5 -8*x^6 -6*x^7 -3*x^8 -x^9)) \\ G. C. Greubel, Mar 03 2017

CROSSREFS

Sequence in context: A000242 A077846 A005322 * A211288 A206727 A211296

Adjacent sequences:  A103777 A103778 A103779 * A103781 A103782 A103783

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Feb 15 2005

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 27 12:08 EDT 2021. Contains 348276 sequences. (Running on oeis4.)