|
| |
|
|
A155196
|
|
a(n)=7*a(n-1)+a(n-2), n>2 ; a(0)=1, a(1)=6, a(2)=42 .
|
|
1
| |
|
|
1, 6, 42, 300, 2142, 15294, 109200, 779694, 5567058, 39749100, 283810758, 2026424406, 14468781600, 103307895606, 737624050842, 5266676251500, 37604357811342, 268497180930894, 1917084624327600, 13688089551224094
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
FORMULA
| G.f.: (1-x-x^2)/(1-7*x-x^2).
a(n)=3*{[(7/2)+(1/2)*sqrt(53)]^(n-1)+[(7/2)-(1/2)*sqrt(53)]^(n-1)}+(21/53)*sqrt(53)*{[(7/2)+(1/2)*sqrt(53)]^(n-1)-[(7/2)-(1/2)*sqrt(53)]^(n-1)}+[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava (paoloplava(AT)gmail.com), Jan 26 2009]
a(n) = Sum_{k, 0<=k<=n} A155161(n,k)*6^k. - DELEHAM Philippe, Feb 08 2012
|
|
|
CROSSREFS
| Sequence in context: A110711 A156361 A055272 * A147838 A127628 A111602
Adjacent sequences: A155193 A155194 A155195 * A155197 A155198 A155199
|
|
|
KEYWORD
| nonn,easy,changed
|
|
|
AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 21 2009
|
| |
|
|
