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A144863 Start with 1, then at each step prepend 10 and append 01. 1
1, 10101, 101010101, 1010101010101, 10101010101010101, 101010101010101010101, 1010101010101010101010101, 10101010101010101010101010101, 101010101010101010101010101010101 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Bisection of A094028. - Omar E. Pol (info(AT)polprimos.com), Nov 12 2008

a(n) is also A144864(n) written in base 2. - Omar E. Pol (info(AT)polprimos.com), Nov 13 2008

Quadrisection of A147759. - Omar E. Pol (info(AT)polprimos.com), Nov 16 2008

LINKS

Index to sequences with linear recurrences with constant coefficients, signature (10001,-10000).

FORMULA

a(n) = (-1+100^(-1+2*n))/99.

If a(n) is interpreted as binary number, (-4+16^n)/12 gives the decimal representation of a(n).

a(n) = 10000*a(n-1)+101, n>1.

G.f.: x*(1+100*x) / ( (10000*x-1)*(x-1) ).

MATHEMATICA

a = {}; k = {1}; Do[x = FromDigits[k, 2]; AppendTo[a, FromDigits[RealDigits[x, 2]]]; AppendTo[k, 0]; AppendTo[k, 1]; PrependTo[k, 0]; PrependTo[k, 1], {n, 1, 100}];

Table[FromDigits[RealDigits[1/12 (-4 + 16^n), 2]], {n, 1, 10}]

a = {}; k = 1; Do[AppendTo[a, k]; k = 10000 k + 101, {n, 1, 10}]; a

Table[1/99 (-1 + 100^(-1 + 2 n)), {n, 1, 20}]

CROSSREFS

Cf. A056830, A094028, A135576, A144864, A147759.

Sequence in context: A193241 A043641 A114385 * A058042 A161786 A157711

Adjacent sequences:  A144860 A144861 A144862 * A144864 A144865 A144866

KEYWORD

base,nonn,easy

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Sep 23 2008, Sep 25 2008

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Last modified February 16 16:51 EST 2012. Contains 205938 sequences.