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A100825
In decimal representation: minimal number of editing steps (delete, insert, or substitute) to transform 2^n into its reversal.
0
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
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
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Jan 06 2005
STATUS
approved