OFFSET
0,2
REFERENCES
Simmons, G. J. The structure of the differentiation digraphs of binary sequences. Ars Combin. 35 (1993), A, 71-88. Math. Rev. 95f:05052.
FORMULA
If n=b_k b_{k-1} ... b_0 in base 3, a(n) is number with ternary expansion (b_k+b_{k-1}) (b_{k-1}+b_{k-2}) ... (b_1+b_0) (b_0+b_{k}).
EXAMPLE
14=112->200 so a(14)=18.
CROSSREFS
KEYWORD
nonn,nice,easy
AUTHOR
EXTENSIONS
Corrected and extended by Naohiro Nomoto, Apr 08 2001
STATUS
approved
