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%I #31 Feb 27 2018 02:59:52
%S 0,10,78,153,946,177310,450775,13595505,150988753,4478601403,
%T 5409300078,5589152128,76060335351,248156250265,1793751529485,
%U 176149383165876,187718592284301,233626949305596,11362376565228270,18886935830647605,1943937379018997076
%N Triangular numbers that for some k are also the sum of the first k composites.
%e 10 is a term because 10 = 1 + 2 + 3 + 4 = 4 + 6.
%o (PARI) lista(nn) = {my(s=0); forcomposite(n=0, nn, if(ispolygonal(s, 3), print1(s, ", ")); s += n; ); } \\ after _Michel Marcus_ at A053767
%Y Intersection of A000217 and A053767.
%Y Cf. A066527, A154587, A294174.
%K nonn
%O 1,2
%A _Altug Alkan_, Feb 15 2018
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