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Numbers that are not the sum of consecutive triangular numbers.
4

%I #16 Dec 23 2015 14:30:51

%S 2,5,7,8,11,12,13,14,17,18,22,23,24,26,27,29,30,32,33,37,38,39,40,41,

%T 42,43,44,47,48,50,51,53,54,57,58,59,60,61,62,63,65,67,68,69,70,71,72,

%U 73,75,76,77,79,82,86,87,88,89,90,92,93,94,95,96,97

%N Numbers that are not the sum of consecutive triangular numbers.

%C Numbers that are not the difference of two tetrahedral numbers. - _Franklin T. Adams-Watters_, Dec 16 2015

%H Reinhard Zumkeller, <a href="/A050941/b050941.txt">Table of n, a(n) for n = 1..10000</a>

%t lim = 20; Take[#, Floor[Length[#]/lim]] &@ Complement[Range@ Max@ #, #] &@ Union[Subtract @@@ Map[Sort[#, Greater] &, Permutations[Table[Binomial[n + 2, 3], {n, 0, lim}], {2}]]] (* _Michael De Vlieger_, Dec 17 2015, in part after _Zerinvary Lajos_ at A000292 *)

%o (Haskell)

%o import Data.List.Ordered (minus)

%o a050941 n = a050941_list !! (n-1)

%o a050941_list = minus [0..] a034706_list

%o -- _Reinhard Zumkeller_, May 12 2015

%Y Complement of A034706.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Jan 02 2000