A109880 Numbers k such that k and its digit reversal both are difference of successive cubes.
1, 7, 19, 91, 127, 721, 919, 14491, 19441, 113491, 177877, 194311, 778771, 1081801, 1188811, 1767169, 1927207, 1946491, 7027291, 9617671, 16056847, 74775169, 74865061, 96157747, 129869461, 164968921, 167828761, 180676081, 189202267, 757333297, 762202981, 792333757, 1917766117, 7116677191
Offset: 1
Examples
19 = 3^3-2^3 and 91 = 6^3-5^3.
Crossrefs
Cf. A109879.
Programs
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Mathematica
okQ[x_]:=Module[{revx=FromDigits[Reverse[IntegerDigits[x]]]},And@@(And@@IntegerQ/@(n/.Solve[1+3n+3n^2==x,n])&&And@@IntegerQ/@(n/.Solve[1+3n+3n^2==revx,n]))]; Select[Range[20000], okQ] (* Harvey P. Dale, Aug 06 2007 *)
Extensions
More terms from Harvey P. Dale, Aug 06 2007
23 more terms from Donovan Johnson, Feb 21 2008
Comments