0,2

a(n)/6^n tends to 0.65946...

S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 322-331.

Table of n, a(n) for n=0..20.

S. R. Finch, Polya's Random Walk Constants

a(2n) = 6*a(2n-1)-A049037(n); a(2n+1) = 6*a(2n).

a(2) = 30 since there are 36 2-step walks but 6 of them involve a return to the origin at some stage; similarly a(3) = 180 since there are 216 3-step walks but 36 of them involve a return to the origin at some stage.

Sequence in context: A089896 A057754 A001473 * A029571 A259276 A109501

Adjacent sequences: A063885 A063886 A063887 * A063889 A063890 A063891

nonn

Henry Bottomley, Aug 28 2001

approved