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A085804
Least k such that n^n + k is a palindrome.
0
0, 0, 6, 6, 98, 8, 885, 545, 4294, 1, 542971, 567942, 4985950, 34463095, 817539359, 3335212865, 1825278551, 60542888969, 351980024812, 6758401, 13316726728064, 355067132000559, 10940544943498235, 100371505302529555, 98630474467606263
OFFSET
1,3
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]]]]]]]]; f[n_] := Block[{}, If[ FromDigits[ Reverse[ IntegerDigits[n^n]]] == n^n, 0, NextPalindrome[n^n] - n^n]];
CROSSREFS
Sequence in context: A347916 A361738 A320824 * A012125 A267139 A170915
KEYWORD
base,nonn
AUTHOR
Jason Earls, Jul 24 2003
EXTENSIONS
Edited and extended by Robert G. Wilson v, Jul 26 2003
STATUS
approved