OFFSET
2,1
COMMENTS
Define f_b(x) to be the set of base b numbers left after splitting 2x at its zero digits and Image_b(S) = union_{x in S}{ { x } union f_b(S) }, then a(n) = | Image_n^inf({ 2 }) |.
LINKS
Hugo van der Sanden, Table of n, a(n) for n = 2..62
Hugo van der Sanden, Perl and C implementations, Feb 03 2015
EXAMPLE
a(8) = 3 since f_8(2) = { 4 }, f_8(4) = { 1 }, f_8(1) = { 2 } so Image_8^inf({ 2 }) = { 1, 2, 4 } and |{ 1, 2, 4 }| = 3.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Hugo van der Sanden, Feb 03 2015
STATUS
approved