A288148 Number of (undirected) paths in the n-triangular grid graph.

0, 6, 108, 2598, 123750, 12994248, 3114709914, 1730766715308, 2248937669398650, 6877862090075063484, 49790967547432817528562, 857275977287938332061154856, 35233501393224883314185777947590

Offset

0,2

Comments

Paths of length zero are not counted here.

Links

Table of n, a(n) for n=0..12.

Eric Weisstein's World of Mathematics, Graph Path

Eric Weisstein's World of Mathematics, Triangular Grid Graph

Example

a(1) = 6:
:    o    :    o    :    o    :    o    :    o    :    o
:         :   /     :     \   :   / \   :     \   :   /
:  o---o  :  o   o  :  o   o  :  o   o  :  o---o  :  o---o  .

Crossrefs

Cf. A020874, A266513, A112675, A112676.

Sequence in context: A361728 A055532 A369532 * A010563 A114310 A221954

Adjacent sequences: A288145 A288146 A288147 * A288149 A288150 A288151

Keyword

nonn,more

Author

Eric W. Weisstein, Jun 05 2017

Extensions

a(7)-a(12) from Andrew Howroyd, Jun 07 2017

Status

approved