0,1

seq(a[3*n+2]/14,n=0..9) = 1, 15, 487, 12507, 342811, 9214935, 249130927, 6723913587, 181566638371, 4902131463855

seq(a[3*n+1]/98,n=0..9) =0, 1, 21, 613, 16185, 439921, 11854461, 320257693, 8645459745, 233439396841

seq(a[2*n+1]/6,n=0..14) =0, 3, 35, 343, 3195, 29183, 264355, 2386023, 21501515, 193622863, 1743042675, 15689131703, 141209175835, 1270910544543, 11438306748995

seq(a[6*n+1]/294,n=0..4) =0, 7, 5395, 3951487, 2881819915

G.f.: G(x)=(3-7*x^2)/(1-7*x^2-6*x^3) E.g.f: E(x)=exp(-x)+exp(-2*x)+exp(3*x)

a(3)=(-1)^3+(-2)^3+3^3=-1-8+27=18

Adjacent sequences: A135396 A135397 A135398 this_sequence A135400 A135401 A135402

Sequence in context: A058896 A008403 A138349 this_sequence A065121 A138540 A123023

easy,nonn

Miklos Kristof (kristmikl(AT)freemail.hu), Dec 11 2007