|
| |
| |
|
|
|
0, 4, 16, 52, 160, 484, 1456, 4372, 13120, 39364, 118096, 354292, 1062880, 3188644, 9565936, 28697812, 86093440, 258280324, 774840976, 2324522932, 6973568800, 20920706404, 62762119216, 188286357652, 564859072960, 1694577218884
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| a(n) is the number of steps which are made when generating all n-step nonreversing random walks that begin in a fixed point P on a two-dimensional square lattice. To make one step means to move along one edge on the lattice.
a(n)=A048473(n) - 1. [From Paul Curtz (bpcrtz(AT)free.fr), Jan 19 2009]
|
|
|
LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..196
|
|
|
FORMULA
| a(n)=2*(3^n - 1);
a(0)=0, a(n)=4*Sum_{i = 0 to n-1} 3^i for n>0;
a(n)=4*A003462
|
|
|
MATHEMATICA
| a=0; lst={a}; Do[a=a*3+4; AppendTo[lst, a], {n, 0, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 25 2008]
|
|
|
PROG
| (MAGMA) [2*(3^n - 1): n in [0..25] ]; // Vincenzo Librandi, Apr 30 2011
|
|
|
CROSSREFS
| Cf. A003462, A007051, A034472, A024023, A067771, A029858, A134931, A115099, A100774, A079004, A058481 [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 25 2008]
Sequence in context: A188125 A007688 A197132 * A107767 A087972 A074409
Adjacent sequences: A100771 A100772 A100773 * A100775 A100776 A100777
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Pawel P. Mazur (Pawel.Mazur(AT)pwr.wroc.pl), Apr 06 2005
|
| |
|
|
