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

1,5

Links

Table of n, a(n) for n=1..83.

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)).

Example

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.

Crossrefs

Sequence in context: A118177 A105069 A172008 * A216452 A307616 A202709

Adjacent sequences: A100822 A100823 A100824 * A100826 A100827 A100828

Keyword

nonn,base

Author

Reinhard Zumkeller, Jan 06 2005

Status

approved