

A060824


4wave sequence beginning with 2s.


0



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
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

2,1


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 <n, called proper divisors).


LINKS

Table of n, a(n) for n=2..44.
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).


FORMULA

a(n) = 2*A038197(n2).
a(n)=2*a(n3)+3*a(n6)a(n9)a(n12)  Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jan 12 2003
G.f.: 2*x^2*(x^52*x^4+2*x^3x^21)/((x^2x+1)*(x^93*x^3+1)).  Colin Barker, Nov 09 2012


CROSSREFS

Cf. A038197.
Sequence in context: A126663 A032600 A103260 * A244459 A064849 A269302
Adjacent sequences: A060821 A060822 A060823 * A060825 A060826 A060827


KEYWORD

easy,nonn


AUTHOR

Jason Earls, May 01 2001


STATUS

approved



