OFFSET
1,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000 (first 100 terms from Muhammad Kholilurrohman)
FORMULA
G.f.: -(8*x^10 +17*x^9 -38*x^8 -60*x^7 +74*x^6 +55*x^5 -56*x^4 -10*x^3 +6*x^2 +2*x) / (4*x^12 -20*x^11 -71*x^10 +116*x^9 +197*x^8 -268*x^7 -129*x^6 +252*x^5 -31*x^4 -80*x^3 +26*x^2 +8*x -1). - Alois P. Heinz, Nov 16 2014
EXAMPLE
The 22 paths in a 2 X 2 grid whose nodes are numbered from 1 to 4 in the natural way are 124, 134, 12124, 12134, 12424, 12434, 13124, 13134, 13424, 13434, 1212434, 1213424, 1213434, 1242134, 1243124, 1243134, 1312424, 1312434, 1313424, 1342124, 1342134, 1343124.
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Resta, Mar 24 2014
EXTENSIONS
a(21)-a(40) from Muhammad Kholilurrohman, Nov 16 2014
STATUS
approved