A100825 In decimal representation: minimal number of editing steps (delete, insert, or substitute) to transform 2^n into its reversal.

0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 4, 4, 4, 4, 4, 4, 2, 6, 6, 4, 6, 4, 4, 4, 4, 6, 6, 8, 6, 8, 8, 8, 8, 8, 8, 8, 6, 6, 10, 12, 12, 8, 10, 10, 12, 10, 10, 14, 14, 14, 12, 12, 14, 12, 10, 14, 14, 16, 16, 16, 18, 14, 16, 16, 16, 14, 18, 16, 18, 18, 18, 18, 18, 16, 20, 20, 18, 22, 22, 22, 20, 18, 20

Offset: 1

Author

Reinhard Zumkeller, Jan 06 2005

Keywords

• nonn
• base

Examples

			n=19: 2^19 = 524288=[5]24288 -> 824288=[]824288 ->
8824288=882428[8] -> 882428=88242[8] -> 882425=A004094(19):
a(19) = #{subst[5->8], ins[8], del[8], subst[8->5]} = 4.
		

Links

• Michael Gilleland, Levenshtein Distance [It has been suggested that this algorithm gives incorrect results sometimes. - _N. J. A. Sloane_]

Formula

a(n) = LevenshteinDistance(A000079(n), A004094(n)).