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Search: id:A072818
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| A072818 |
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Possibly the only integers of the form sqrt(m^2*(m^2-1)*2/3) [only checked for the first 5 terms]. |
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+0
2
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| 0, 20, 1960, 192060, 18819920, 1844160100, 180708869880, 17707625088140, 1735166549767840, 170028614252160180, 16661069030161929800, 1632614736341616960220, 159979583092448300171760
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OFFSET
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0,2
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COMMENT
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These are the standard deviations of time for a random walk starting at 0 to reach one of the boundaries at +A001079(n) or -A001079(n) for the first time.
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LINKS
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Tanya Khovanova, Recursive Sequences
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FORMULA
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a(n) = 98*a(n-1)-a(n-2) [starting with a(0)=0 and a(1)=20] =sqrt(A072819(A001079(n))).
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EXAMPLE
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0 and 20 are at the start of the sequence since m^2*(m^2-1)*2/3 (A072819) starts 0, 0, 8, 48, 160, 400, 840, 1568, ... and the only squares among these are 0 and 400 with square roots of 0 and 20.
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CROSSREFS
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Sequence in context: A130040 A094035 A014606 this_sequence A123479 A071152 A064878
Adjacent sequences: A072815 A072816 A072817 this_sequence A072819 A072820 A072821
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KEYWORD
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nonn
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), Jul 14 2002
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