|
| |
| |
|
|
|
120, 482, 1086, 1932, 3020, 4350, 5922, 7736, 9792, 12090, 14630, 17412, 20436, 23702, 27210, 30960, 34952, 39186, 43662, 48380, 53340, 58542, 63986, 69672, 75600, 81770, 88182, 94836, 101732, 108870, 116250, 123872, 131736, 139842
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| The identity (242*n-1)^2-(121*n^2-n)*22^2 = 1 can be written as A157961(n)^2-a(n)*22^2 = 1. - Vincenzo Librandi, Feb 10 2012
|
|
|
LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
E. J. Barbeau, Polynomial Excursions, Chapter 10: Diophantine equations (2010), pages 84-85 (row 14 in the first table at p. 85, case d(t) = t*(11^2*t-1)).
|
|
|
FORMULA
| G.f.: x*(-120-122*x)/(x-1)^3. - Vincenzo Librandi, Feb 10 2012
a(n) = 3*a(n-1) -3*a(n-2) +a(n-3). - Vincenzo Librandi, Feb 10 2012
|
|
|
MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {120, 482, 1086}, 50] (* Vincenzo Librandi, Feb 10 2012
|
|
|
PROG
| (MAGMA) I:=[120, 482, 1086]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..50]]; - Vincenzo Librandi, Feb 10 2012
(PARI) for(n=1, 40, print1(121*n^2 - n", ")); \\ Vincenzo Librandi, Feb 10 2012
|
|
|
CROSSREFS
| Cf. A157961.
Sequence in context: A147983 A167562 A033697 * A067915 A115619 A152622
Adjacent sequences: A157957 A157958 A157959 * A157961 A157962 A157963
|
|
|
KEYWORD
| nonn,easy,changed
|
|
|
AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 10 2009
|
| |
|
|
