1,2

Numbers not divisible by 5. - Lekraj Beedassy (blekraj(AT)yahoo.com), Dec 17 2006

G.f.: (x+2*x^2+3*x^3+4*x^4+4*x^5+3*x^6+2*x^7+x^8)/(1-x^4)^2 - Len Smiley (smiley(AT)math.uaa.alaska.edu)

a(n)=5+a(n-4).

G.f.: (1+x+x^2+x^3+x^4)/((1-x)*(1-x^4)).

(PARI) a(n)= 1+n+n\4

Cf. A045572.

Adjacent sequences: A047198 A047199 A047200 this_sequence A047202 A047203 A047204

Sequence in context: A001961 A020656 A039116 this_sequence A023721 A087066 A120518

nonn

njas