A354958 - OEIS

%I #7 Jun 15 2022 11:36:44

%S 1,3,9,15,27,21,45,27,63,33,81,39,99,45,117,51,135,57,153,63,171,69,

%T 189,75,207,81,225,87,243,93,261,99,279,105,297,111,315,117,333,123,

%U 351,129,369,135,387,141,405,147,423,153,441,159,459,165,477,171,495

%N Coordination sequence for the Manhattan hexagonal lattice with respect to the point (X=0, Y=1).

%C In the Manhattan hexagonal lattice, streets parallel to one of the 3 axis have alternating orientations:

%C                Z         Y

%C                 .---<---.

%C                / \     / \

%C               v   ^   ^   v

%C              /     \ /     \

%C             .--->---O--->---. X

%C              \     / \     /

%C               v   ^   ^   v

%C                \ /     \ /

%C                 .---<---.

%H Rémy Sigrist, <a href="/A354958/a354958.png">Illustration of initial terms</a>

%H Rémy Sigrist, <a href="/A354958/a354958.gp.txt">PARI program</a>

%H <a href="/index/Con#coordination_sequences">Index entries for coordination sequences</a>

%H <a href="/index/Aa#A2">Index entries for sequences related to A2 = hexagonal = triangular lattice</a>

%o (PARI) See Links section.

%Y Cf. A008458, A336627, A354957.

%K nonn

%O 0,2

%A _Rémy Sigrist_, Jun 13 2022