login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A281581 a(n) = (15*2^(2*n+2) + 15*2^(n+2) + 5*2^(n+3)*3^(n+1) - 24*5^(n+1))/120. 2
1, 4, 21, 127, 807, 5179, 33111, 210067, 1321887, 8255899, 51225351, 316067107, 1941032367, 11873549419, 72394874391, 440204293747, 2670669533247, 16172309991739, 97779619272231, 590423692897987, 3561340764760527, 21462312506478859 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..1285

Index entries for linear recurrences with constant coefficients, signature (17,-104,268,-240).

FORMULA

G.f.: ( 1-13*x+57*x^2-82*x^3 ) / ( (6*x-1)*(4*x-1)*(2*x-1)*(5*x-1) ). - R. J. Mathar, Mar 19 2017

a(n) = 6^n +2^(n-1)-5^n+4^n/2 . - R. J. Mathar, Mar 19 2017

MATHEMATICA

Table[(15*2^(2*n+2) + 15*2^(n+2) + 5*2^(n+3)*3^(n+1) - 24*5^(n+1)) / 120, {n, 0, 21] (* Indranil Ghosh, Mar 05 2017 *)

PROG

(PARI)

a(n) = (15*2^(2*n+2) + 15*2^(n+2) + 5*2^(n+3)*3^(n+1) - 24*5^(n+1)) / 120;

for (n=0, 21, print1(a(n), ", ")); \\ Indranil Ghosh, Mar 05 2017

(Python) def A281581(n): return (15*2**(2*n+2) + 15*2**(n+2) + 5*2**(n+3)*3**(n+1) - 24*5**(n+1)) / 120 # Indranil Ghosh, Mar 05 2017

(Ruby)

def A281581(n)

  (0..n).map{|i| (15 * 2 ** (2 * i + 2) + 15 * 2 ** (i + 2) + 5 * 2 ** (i + 3) * 3 ** (i + 1) - 24 * 5 ** (i + 1)) / 120}

end

CROSSREFS

Row n=5 of A283272.

Sequence in context: A211249 A185047 A032326 * A007345 A255673 A099250

Adjacent sequences:  A281578 A281579 A281580 * A281582 A281583 A281584

KEYWORD

nonn,easy

AUTHOR

Seiichi Manyama, Mar 05 2017

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 22 13:55 EST 2018. Contains 299454 sequences. (Running on oeis4.)