%I A007527 M3793
%S A007527 5,10,11,20,25,26,38,39,54,65,70,114,130
%N A007527 Numbers that are not the sum of 4 hexagonal numbers.
%C A007527 The sequence is complete. "In 1830, Legendre (1979) proved that every 
               number larger than 1791 is a sum of four hexagonal numbers". See 
               http://mathworld.wolfram.com/HexagonalNumber.html and reference : 
               A.-M. Legendre, Theorie des nombres, 4th ed., 2 vols. Paris: A. Blanchard, 
               1979. It is easy to check all numbers <= 1791 by computer. - Olivier 
               Pirson (olivier_pirson_opi(AT)yahoo.fr), Sep 14 2007
%D A007527 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A007527 R. K. Guy, Every number is expressible as the sum of how many polygonal 
               numbers?, Amer. Math. Monthly 101 (1994), 169-172.
%H A007527 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               HexagonalNumber.html">Hexagonal Number</a>
%Y A007527 Sequence in context: A136822 A120513 A004757 this_sequence A033894 A033649 
               A050680
%Y A007527 Adjacent sequences: A007524 A007525 A007526 this_sequence A007528 A007529 
               A007530
%K A007527 fini,nonn,full
%O A007527 1,1
%A A007527 N. J. A. Sloane (njas(AT)research.att.com).