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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A143860 Ulam's spiral (NNW spoke). 1
1, 16, 63, 142, 253, 396, 571, 778, 1017, 1288, 1591, 1926, 2293, 2692, 3123, 3586, 4081, 4608, 5167, 5758, 6381, 7036, 7723, 8442, 9193, 9976, 10791, 11638, 12517, 13428, 14371, 15346, 16353, 17392, 18463, 19566, 20701, 21868, 23067, 24298 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

LINKS

Index to sequences with linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(n)=16*n^2-33*n+18. [From R. J. Mathar, Sep 08 2008]

G.f. -x*(1+13*x+18*x^2) / (x-1)^3 . - R. J. Mathar, Oct 31 2011

MATHEMATICA

f[n_] := 16n^2 -33n +18; Array[f, 40] (* Robert G. Wilson v, Oct 31 2011 *)

CROSSREFS

Sequence in context: A118254 A066391 A022289 * A100176 A060091 A076751

Adjacent sequences:  A143857 A143858 A143859 * A143861 A143862 A143863

KEYWORD

nonn,easy

AUTHOR

Vladimir Orlovsky (4vladimir(AT)gmail.com), Sep 03 2008

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 15 12:25 EST 2012. Contains 205786 sequences.