A miscellaneous nontriangular matrix product: [ sqrt(%pi) ] [ 0 0 --------- ] [ 1 1 5 1 ] [ 2 3 ] oo [ 0 -- - ----- - - --- ] [ gamma (-) ] /===\ [ 16 2 4 8 j ] [ 4 ] | | [ 64 j ] [ ] | | [ ] = [ 2 3 ] | | [ 1 1 2 ] [ 4 gamma (-) ] j = 1 [ (- - ---) 0 1 ] [ 4 ] [ 2 4 j ] [ 0 0 ----------- ] [ ] [ 3/2 ] [ 0 0 1 ] [ %pi ] [ ] [ 0 0 1 ] (Does anybody know how to make these archaic ASCII displays in Mathematica, for our archaic math-fun server?) A260747, Consolidated Dragon Curve triple points. If D:[0,1] is a Dragon curve, then besides n, there are two other integers p and q with D(A(n)/(15*2^k)) = D(A(p)/(15*2^k)) = D(A(q)/(15*2^k)), where k is any integer > lg(max(A(n),A(p),A(q))/15) 13, 21, 23, 26, 37, 39, 42, 46, 47, 52, 73, 74, 78, 81, 83, 84, 92, 94, 97, 99, Note the gap of 73 - 52 = 21 at position 10. There are apparently no larger gaps, and the next gap of 21 is at position 17651. --rwg