A116185 Numbers k such that k concatenated with k+4 gives the product of two numbers which differ by 3.
150, 186, 324, 376, 666, 2046, 3000, 82650, 100384, 466716, 1322316, 4049584, 67820074, 110003884, 135734074, 156502836, 196043286, 213017754, 238849000, 261405396, 289940826, 310507774, 365294050, 398891964, 446667216
Offset: 1
Programs
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Maple
cc:=proc(x,y) local s: s:=proc(m) nops(convert(m,base,10)) end: x*10^s(y)+y: end: a:=proc(n) if type(sqrt(9+4*cc(n,n+4)),integer) then n else fi end: seq(a(n),n=1..500000); # very slow; cc yields the concatenation of x and y; - Emeric Deutsch, May 05 2007
Extensions
Edited by N. J. A. Sloane, Apr 14 2007
Comments