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A104672 a(n) = C(n+4,4)*C(n+9,n+0). 0
1, 50, 825, 7700, 50050, 252252, 1051050, 3775200, 12033450, 34763300, 92470378, 229265400, 534952600, 1183859600, 2500601400, 5067885504, 9898213875, 18700431750, 34284124875, 61160599500, 106419443130, 180985447500, 301393121250, 492256440000, 789661372500 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..24.

Index entries for linear recurrences with constant coefficients, signature (14,-91,364,-1001,2002,-3003,3432,-3003,2002,-1001,364,-91,14,-1).

FORMULA

From Amiram Eldar, Aug 30 2022: (Start)

Sum_{n>=0} 1/a(n) = 990*Pi^2 - 38297957/3920.

Sum_{n>=0} (-1)^n/a(n) = 15*Pi^2 - 12288*log(2)/7 + 4193253/3920. (End)

EXAMPLE

If n=0 then C(0+4,4)*C(0+9,0+0)= C(4,4)*C(9,0)=1*1=1

If n=6 then C(6+4,4)*C(6+9,6+0)= C(10,4)*C(15,6)=210*5005=1051050

MATHEMATICA

Table[Binomial[n+4, 4]Binomial[n+9, n], {n, 0, 20}] (* Harvey P. Dale, Nov 15 2018 *)

CROSSREFS

Cf. A062190.

Sequence in context: A231835 A206120 A160287 * A086027 A110929 A329713

Adjacent sequences:  A104669 A104670 A104671 * A104673 A104674 A104675

KEYWORD

easy,nonn

AUTHOR

Zerinvary Lajos, Apr 22 2005

EXTENSIONS

More terms from Harvey P. Dale, Nov 15 2018

STATUS

approved

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Last modified September 28 17:45 EDT 2022. Contains 357080 sequences. (Running on oeis4.)