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A065761
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Concatenation of increasing number of alternating digits in base 2, starting with 0.
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3
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0, 3, 24, 399, 12768, 817215, 104603520, 26778501375, 13710592704000, 14039646928897023, 28753196910381103104, 117773094544920998318079, 964797190511992818221703168, 15807237169348490333744384720895
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OFFSET
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1,2
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COMMENTS
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The first 5 terms in base 2 are 0, (0)11, (0)11000, (0)110001111, (0)11000111100000.
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LINKS
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FORMULA
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a(1) = 0; a(n+1) = append n+1 0's or 1's (alternately) to a(n).
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EXAMPLE
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a(5) = 12768 is formed by appending 0 five times (00000) to a(4) in base 2: (0)11000111100000.
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PROG
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(PARI) baseI(x, b)= { local(d, e=0, f=1); while (x>0, d=x-10*(x\10); x\=10; e+=d*f; f*=b); return(e) } { c=1; for (n=1, 50, if (n==1, a=0; b=0, c=c*10 + 1; if (n%2, d=0, d=c); b=b*10^n + d; a=baseI(b, 2)); write("b065761.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 30 2009
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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STATUS
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approved
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