A060827 3-wave sequence beginning with 2's.

2, 2, 2, 4, 6, 10, 12, 22, 28, 50, 62, 112, 140, 252, 314, 566, 706, 1272, 1586, 2858, 3564, 6422, 8008, 14430, 17994, 32424, 40432, 72856, 90850, 163706, 204138, 367844, 458694, 826538, 1030676, 1857214, 2315908, 4173122, 5203798, 9376920

Offset: 0

Author

Jason Earls, Apr 30 2001

Keywords

• easy
• nonn

Comments

The 3-wave sequence with initial values a, b, c is formed by the following construction:

a.......a+b+c............3a+5b+6c...

..b...b+c...a+2b+2c..2a+4b+5c...

....c..........a+2b+3c...

Dropping middle row gives A052994.

Links

• F. v. Lamoen, Wave sequences
• Index entries for linear recurrences with constant coefficients, signature (0,2,0,1,0,-1).

Crossrefs

Cf. A038196, A052994 (bisection)

Formula

G.f.: (-2x^2+2x+2)/(x^6-x^4-2x^2+1).

a(n) = 2*A038196(n).

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 10 2001