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 A038862 Numbers ending with '7' that are the difference of two positive cubes. 1
 7, 37, 117, 127, 217, 387, 397, 547, 657, 817, 1027, 1197, 1267, 1387, 1647, 1657, 1727, 2107, 2437, 2457, 2717, 2977, 3087, 3367, 3997, 4167, 4447, 4697, 4977, 5167, 5677, 5707, 6327, 6347, 6487, 6517, 7057, 7317, 7657, 7957, 8587, 8937, 9197, 9317 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 MAPLE filter:= proc(n) local t, y, r; for t in sort(convert(numtheory:-divisors(n), list)) do r:= 12*n*t-3*t^4; if r < 0 then return false fi; if not issqr(r) then next fi; y:= (sqrt(r)-3*t^2)/(6*t); if y::posint then return true fi od; false end proc: select(filter, [seq(i, i=7..10000, 10)]); # Robert Israel, Aug 08 2019 MATHEMATICA With[{nn=60}, Select[Union[#[[2]]-#[[1]]&/@Subsets[Range[nn]^3, {2}]], Mod[#, 10] == 7&&#

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Last modified December 6 05:22 EST 2022. Contains 358594 sequences. (Running on oeis4.)