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!)
A117614 a(0)=1, a(n)=4a(n-1)+2 for n odd, a(n)=4a(n-1) for n even. 0
1, 6, 24, 98, 392, 1570, 6280, 25122, 100488, 401954, 1607816, 6431266, 25725064, 102900258, 411601032, 1646404130, 6585616520, 26342466082, 105369864328, 421479457314, 1685917829256, 6743671317026, 26974685268104 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

L. Rosenfeld, Nuclear Forces, section II, Interscience, New York, 1948, p 202.

LINKS

Table of n, a(n) for n=0..22.

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

FORMULA

a(n) = (-5-3*(-1)^n+23*4^n)/15. a(n) = 4*a(n-1)+a(n-2)-4*a(n-3). G.f.: -(x^2-2*x-1) / ((x-1)*(x+1)*(4*x-1)). [Colin Barker, Feb 17 2013]

MAPLE

a:=proc(n) if n=0 then 1 elif n mod 2 = 1 then 4*a(n-1)+2 else 4*a(n-1) fi end: seq(a(n), n=0..25);

MATHEMATICA

b[0] := 1 b[1] := 6 b[n_?EvenQ] := b[n] = 4*b[n - 1] b[n_?OddQ] := b[n] = 4*b[n - 1] + 2 a = Table[b[n], {n, 0, 25}]

CROSSREFS

Sequence in context: A290911 A037505 A048179 * A037688 A255471 A126393

Adjacent sequences:  A117611 A117612 A117613 * A117615 A117616 A117617

KEYWORD

nonn,easy

AUTHOR

Roger L. Bagula, Apr 07 2006

EXTENSIONS

Edited by N. J. A. Sloane, Apr 16 2006

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 August 15 16:02 EDT 2020. Contains 336505 sequences. (Running on oeis4.)