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!)
A128498 Fourth column (m=3) of triangle A128494. 3
1, 1, -3, -3, 7, 7, -13, -13, 22, 22, -34, -34, 50, 50, -70, -70, 95, 95, -125, -125, 161, 161, -203, -203, 252, 252, -308, -308, 372, 372, -444, -444, 525, 525, -615, -615, 715, 715, -825, -825, 946, 946, -1078, -1078, 1222, 1222, -1378, -1378, 1547, 1547, -1729, -1729, 1925, 1925, -2135, -2135 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Unsigned, this is the repeated sequence A002623.

LINKS

Table of n, a(n) for n=0..55.

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

FORMULA

G.f.: 1/((1-x)*(1+x^2)^4).

a(2*k) = a(2*k+1)= ((-1)^k)*A002623(n), k>=0.

a(n) = (-1)^((2*n-1+(-1)^n)/4)*((n+2)*(n+7)*(2*n+9)+3*(n+3)*(n+6)*(-1)^n+12*(-1)^((2*n-1+(-1)^n)/4))/192. - Luce ETIENNE, Mar 13 2015

PROG

(PARI) Vec(1/((1-x)*(1+x^2)^4) + O(x^50)) \\ Michel Marcus, Mar 16 2015

CROSSREFS

Cf. A008642 (unsigned column m=2). A128499 (column m=4).

Sequence in context: A128508 A083743 A126990 * A146906 A147449 A325344

Adjacent sequences:  A128495 A128496 A128497 * A128499 A128500 A128501

KEYWORD

sign,easy

AUTHOR

Wolfdieter Lang, Apr 04 2007

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 July 9 03:16 EDT 2020. Contains 335538 sequences. (Running on oeis4.)