A033629 - OEIS

%I #17 Dec 02 2018 09:06:00

%S 23,25,33,35,43,45,67,92,94,96,111,121,136,143,160,165,170,172,187,

%T 194,204,226,231,248,265,270,280,287,292,297,302,304,314,331,336,346,

%U 348,353,368,380,397,407,419,424,446,463,468,473,475,480,490,495,507

%N Numbers that are not the sum of two distinct Ulam numbers.

%D R. K. Guy, Unsolved Problems in Number Theory, C4

%H T. D. Noe, <a href="/A033629/b033629.txt">Table of n, a(n) for n=1..1000</a>

%H Ivano Salvo, Agnese Pacifico, <a href="https://arxiv.org/abs/1807.11792">Computing Integer Sequences: Filtering vs Generation (Functional Pearl)</a>, arXiv:1807.11792 [cs.PL], 2018.

%t terms = 1000; ulams = {1, 2};

%t Do[AppendTo[ulams, n = Last[ulams]; While[n++; Length[ DeleteCases[ Intersection[ ulams, n - ulams], n/2, 1, 1]] != 2]; n], {terms}];

%t uu = Total /@ Subsets[ulams, {2}] // Union;

%t Complement[Range[Last[uu]], uu] // Take[#, {3, terms+2}]& (* _Jean-François Alcover_, Dec 02 2018 *)

%Y Cf. A002858.

%K nonn

%O 1,1

%A _Jud McCranie_