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A256077
Repeat 2^d times the repunit A002275(d); d = 1, 2, 3...
7
1, 1, 11, 11, 11, 11, 111, 111, 111, 111, 111, 111, 111, 111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 1111, 11111, 11111, 11111, 11111, 11111, 11111, 11111, 11111, 11111, 11111, 11111, 11111
OFFSET
1,3
COMMENTS
Yields the length of the n-th (nonempty) binary word (or word over any 2-letter alphabet, like A007931 or A032810 or A032834) in tally mark notation (A000042).
LINKS
FORMULA
a(n) = A002275(A000523(n+1)) = A032810(n)-A007931(n) = A032834(n)-A032810(n), etc.
MATHEMATICA
lim = 5; lst = Table[(10^n - 1)/9, {n, 0, lim}]; Reap@ For[i = 1, i <= lim, i++, Sow@ Table[lst[[i + 1]], {d, 2^i}]] // Flatten // Rest (* Michael De Vlieger, Apr 01 2015 *)
PROG
(PARI) a(n)=10^#binary(n+1)\90
CROSSREFS
Sequence in context: A090862 A291498 A290656 * A287503 A286863 A288121
KEYWORD
nonn
AUTHOR
M. F. Hasler, Mar 21 2015
STATUS
approved