Many excellent designs for a new banner were submitted. We will use the best of them in rotation.
0,2
Table of n, a(n) for n=0..9.
Conjecture: a(n) = 9^n/2+3*7^n/2-2*5^n. a(n)= +21*a(n-1) -143*a(n-2) +315*a(n-3). G.f.: x*(-5+41*x)/((9*x-1)*(7*x-1)*(5*x-1)). [R. J. Mathar, May 24 2010]
Sequence in context: A193184 A180787 A222455 * A054937 A193222 A073179
Adjacent sequences: A178292 A178293 A178294 * A178296 A178297 A178298
nonn
R. H. Hardin, suggested by R. J. Mathar in the Sequence Fans Mailing List, May 24 2010
approved