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%I #16 Apr 05 2015 11:02:35
%S 1,3,3,3,6,6,6,10,10,10,15,15,15,15,15,15,21,21,21,21,21,21,28,28,28,
%T 28,28,28,36,36,36,36,36,36,36,36,36,36,45,45,45,45,45,45,45,45,45,45,
%U 55,55,55,55,55,55,55,55,55,55,66,66,66,66,66,66,66,66,66,66,66,66
%N Golomb-type sequence over triangular numbers.
%C All terms are triangular numbers; a(n) is length of n-th run.
%C It is understood that a(n) is taken to be the smallest number >= a(n-1) which is compatible with the description.
%C The apparent idempotence, a(a(n))=a(n), holds while n<191 and breaks after that. - _Ivan Neretin_, Apr 03 2015
%H Ivan Neretin, <a href="/A013322/b013322.txt">Table of n, a(n) for n = 1..10000</a>
%p A:= 1,3,3,3:
%p for n from 4 to 30 do
%p t:= n*(n-1)/2;
%p A:= A, t$A[n-1]
%p od:
%p A; # _Robert Israel_, Apr 03 2015
%t a = {1, 3, 3, 3}; Do[a = Join[a, Array[i(i+1)/2&, a[[i]]]], {i, 3, 11}]; a (* _Ivan Neretin_, Apr 03 2015 *)
%Y Cf. A001462.
%K nonn,easy
%O 1,2
%A _N. J. A. Sloane_
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