%I A090461
%S A090461 15,16,17,23,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,
%T A090461 44,45,46,47,48,49,50
%N A090461 Numbers n such that there is a permutation of the numbers 1 to n such 
               that the sum of adjacent numbers is a square.
%C A090461 Conjecture that there is a solution for all n > 24. See A090460 for a 
               count of the number of essentially different solutions.
%e A090461 See A071983
%Y A090461 Cf. A071983, A071984 (number of circular solutions), A090460.
%Y A090461 Cf. A078107 (n for which there is no solution).
%Y A090461 Sequence in context: A165836 A094836 A004504 this_sequence A138598 A160661 
               A114841
%Y A090461 Adjacent sequences: A090458 A090459 A090460 this_sequence A090462 A090463 
               A090464
%K A090461 nonn
%O A090461 1,1
%A A090461 T. D. Noe (noe(AT)sspectra.com), Dec 01 2003