%I A092360
%S A092360 0,1,1,3,5,8,13,14,28,43,45,89,135,138,143,284,430,438,451,897,1356,
%T A092360 1404,1446,2878,4352,4423,4511,4645,9245,13979,14203,14476,14757,15184,
%U A092360 30225,45693,46407,47275,48164,49512,98573,148982,151235,153968,156749
%N A092360 Spiro-tribonacci numbers: a(n) = sum of three previous terms that are 
               nearest when terms arranged in a spiral.
%e A092360 Terms are written in square boxes radiating spirally (cf. Ulam prime 
               spiral). a(0) = 0, a(1) = 1 and a(2) = 1, so write 0, then 1 to its 
               right. and another 1 below the first 1. The next unfilled box forms 
               a square with the three filled boxes, so a(3) = a(0) + a(1) + a(2) 
               = 0 + 1 + 1 = 2.
%e A092360 ..............
%e A092360 ... 8 13 14 28
%e A092360 ... 5 .0 .1..
%e A092360 ... 3 .2 .1..
%e A092360 .............
%e A092360 a(4) = 2 because a(0) + a(1) + a(2) = 0 + 1 + 1 = 2
%Y A092360 Cf. A078510, A092369.
%Y A092360 Sequence in context: A147879 A147880 A020643 this_sequence A129141 A097431 
               A123929
%Y A092360 Adjacent sequences: A092357 A092358 A092359 this_sequence A092361 A092362 
               A092363
%K A092360 easy,nonn
%O A092360 0,4
%A A092360 Michael Joseph Halm (hierogamous(AT)lycos.com), Apr 02 2004; corrected 
               Apr 05 2004