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A038808
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Palindromic numbers which are the difference of two positive cubes.
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0
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0, 7, 919, 999, 25352, 27872, 31213, 37973, 45054, 53135, 54845, 56765, 60606, 62426, 63936, 74347, 75357, 78687, 86868, 90909, 98289, 121121, 757757, 982289, 999999, 1063601, 1081801, 1188811, 1197911, 1366631, 1393931, 1507051, 1644461
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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MATHEMATICA
| NextPalindrome[n_] := Block[ {l = Floor[ Log[10, n] + 1], idn = IntegerDigits[n]}, If[ Union[ idn] == {9}, Return[n + 2], If[l < 2, Return[n + 1], If[ FromDigits[ Reverse[ Take[ idn, Ceiling[l/2]]]] > FromDigits[ Take[ idn, -Ceiling[l/2]]], FromDigits[ Join[ Take[ idn, Ceiling[l/2]], Reverse[ Take[ idn, Floor[l/2]]]]], idfhn = FromDigits[ Take[ idn, Ceiling[l/2]]] + 1; idp = FromDigits[ Join[ IntegerDigits[ idfhn], Drop[ Reverse[ IntegerDigits[ idfhn]], Mod[l, 2]]]]]]]]; t1 = NestList[ NextPalindrome, 0, 2800]; t2 = Select[ Union[Flatten[Table[n^3 - m^3, {n, 900}, {m, n - 1}]]], # < 2*10^6 &]; Intersection[t1, t2] - Robert G. Wilson v (rgwv(AT)rgwv.com)
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CROSSREFS
| Cf. A002113, A038593, A109879.
Sequence in context: A093171 A177908 A127102 * A068728 A028990 A151579
Adjacent sequences: A038805 A038806 A038807 * A038809 A038810 A038811
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KEYWORD
| nonn,base
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AUTHOR
| Jeff Burch (gburch(AT)erols.com)
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 14 2005
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