|
| |
|
|
A156639
|
|
169n^2 - 140n + 29.
|
|
4
| |
|
|
58, 425, 1130, 2173, 3554, 5273, 7330, 9725, 12458, 15529, 18938, 22685, 26770, 31193, 35954, 41053, 46490, 52265, 58378, 64829, 71618, 78745, 86210, 94013, 102154, 110633, 119450, 128605, 138098, 147929, 158098
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| The identity (57122*n^2-47320*n+9801)^2-(169*n^2-140*n+29)*(4394*n-1820)^2=1 can be written as A156721(n)^2-a(n)*A156627(n)^2=1.
|
|
|
LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Index to sequences with linear recurrences with constant coefficients, signature (3,-3,1).
|
|
|
FORMULA
| a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
G.f.: x*(-58-251*x-29*x^2)/(x-1)^3.
|
|
|
MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {58, 425, 1130}, 40]
|
|
|
PROG
| (MAGMA) I:=[58, 425, 1130]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]];
(PARI) a(n)=169*n^2-140*n+29 \\ Charles R Greathouse IV, Dec 23 2011
|
|
|
CROSSREFS
| Cf. A156627, A156721.
Sequence in context: A051972 A027987 A141779 * A204470 A172215 A157252
Adjacent sequences: A156636 A156637 A156638 * A156640 A156641 A156642
|
|
|
KEYWORD
| nonn,easy
|
|
|
AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 15 2009
|
|
|
EXTENSIONS
| Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Jul 25 2010
|
| |
|
|
