|
| |
|
|
A103142
|
|
a(n) = 2*a(n-1) + a(n-2) + a(n-3) + a(n-4).
|
|
4
| |
|
|
1, 2, 5, 13, 34, 88, 228, 591, 1532, 3971, 10293, 26680, 69156, 179256, 464641, 1204374, 3121801, 8091873, 20974562, 54367172, 140922580, 365278767, 946821848, 2454212215, 6361447625, 16489208080, 42740897848, 110786663616, 287164880785, 744346531114
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Row sums of generalized Pascal matrix A103141.
Generalized Pell numbers.
|
|
|
LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..500
Index entries for sequences related to linear recurrences with constant coefficients, signature (2,1,1,1).
|
|
|
FORMULA
| a(n) = 2*a(n-1) + a(n-2) + a(n-3) + a(n-4).
G.f.: 1/(1-2*x-x^2-x^3-x^4)
|
|
|
MATHEMATICA
| LinearRecurrence[{2, 1, 1, 1}, {1, 2, 5, 13}, 60] (* From Vladimir Joseph Stephan Orlovsky, Jun 20 2011 *)
|
|
|
PROG
| (PARI) Vec(1/(1-2x-x^2-x^3-x^4)+O(x^99)) \\ Charles R Greathouse IV, Jun 20 2011
(MAGMA) I:=[1, 2, 5, 13]; [n le 4 select I[n] else 2*Self(n-1)+Self(n-2)+Self(n-3)+Self(n-4): n in [1..40]]; // Vincenzo Librandi, Feb 05 2012
|
|
|
CROSSREFS
| Cf. A077939, A000129.
Sequence in context: A154101 A122024 A027931 * A112844 A027933 A141448
Adjacent sequences: A103139 A103140 A103141 * A103143 A103144 A103145
|
|
|
KEYWORD
| easy,nonn,changed
|
|
|
AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Jan 24 2005
|
| |
|
|
