%I A001354
%S A001354 1,7,21,56,147,385,1008,2639,6909,18088,47355,123977,324576,
%T A001354 849751,2224677,5824280,15248163,39920209,104512464,273617183,
%U A001354 716339085,1875400072,4909861131,12854183321
%N A001354 Coordination sequence for hyperbolic tesselation 3^7 (from triangle group 
               (2,3,7)).
%F A001354 a(n+1)=3*a(n)-a(n-1).
%Y A001354 7 times alternate Fibonacci numbers A001906.
%Y A001354 Sequence in context: A146408 A050894 A146464 this_sequence A088656 A146139 
               A083596
%Y A001354 Adjacent sequences: A001351 A001352 A001353 this_sequence A001355 A001356 
               A001357
%K A001354 nonn
%O A001354 0,2
%A A001354 N. J. A. Sloane (njas(AT)research.att.com).