A060824 4-wave sequence beginning with 2s.

2, 2, 2, 2, 4, 6, 8, 14, 18, 20, 38, 52, 60, 112, 150, 170, 320, 432, 492, 924, 1244, 1414, 2658, 3582, 4074, 7656, 10314, 11728, 22042, 29698, 33772, 63470, 85512, 97240, 182752, 246222, 279994, 526216, 708968, 806208, 1515176, 2041392, 2321386

Offset: 2

Author

Jason Earls, May 01 2001

Keywords

• easy
• nonn

Comments

Primes are the numbers >=2 which have no nontrivial divisor: a(p)=0.

Also: a(n)= A032741(n)-1, n>=2 (from number of divisors

Links

• F. v. Lamoen, Wave sequences
• Index entries for linear recurrences with constant coefficients, signature (1, -1, 3, -3, 3, 0, 0, 0, -1, 1, -1).

Crossrefs

Cf. A038197.

Formula

a(n) = 2*A038197(n-2).

a(n)=2*a(n-3)+3*a(n-6)-a(n-9)-a(n-12) - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jan 12 2003

G.f.: -2*x^2*(x^5-2*x^4+2*x^3-x^2-1)/((x^2-x+1)*(x^9-3*x^3+1)). - Colin Barker, Nov 09 2012

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