

A319953


List of binary words of lengths 0, 1, 2, etc., including empty word, each prefixed by a 2.


3



2, 20, 21, 200, 201, 210, 211, 2000, 2001, 2010, 2011, 2100, 2101, 2110, 2111, 20000, 20001, 20010, 20011, 20100, 20101, 20110, 20111, 21000, 21001, 21010, 21011, 21100, 21101, 21110, 21111, 200000, 200001, 200010, 200011, 200100, 200101, 200110, 200111
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OFFSET

0,1


LINKS



FORMULA



PROG

(PARI) a(n) = my (b=binary(n+1)); b[1]++; fromdigits(b) \\ Rémy Sigrist, Oct 04 2018
(Python)
def a(n): return int(bin(n)[2:].replace('1', '2', 1))


CROSSREFS



KEYWORD

nonn,base


AUTHOR



EXTENSIONS



STATUS

approved



