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A173428
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The smallest prime appearing in the truncated version of the decimal expansion of (Golden Ratio)^n shifted iteratively left.
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0
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1618033, 2618033988749, 42360679, 6854101, 1109, 179, 2903, 469787, 760131556174964248389559523684316960024905121133959373, 1229, 19900502499874064149, 32199689437, 5210019193, 8429
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OFFSET
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1,1
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COMMENTS
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The n-th power of the golden ratio A001622 is successively shifted left, building floor(A001622^n *10^k) for k = 0, 1, 2, 3,...
As soon as this becomes a prime, we let a(n) be this prime.
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LINKS
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Eric Weisstein's World of Mathematics, Phi-Prime
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EXAMPLE
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1618033 is the first prime found in the decimal expansion of Golden Ratio A001622, after 6 shifts to the left.
2618033988749 is the first prime found in the decimal expansion of (Golden Ratio)^2, A104457.
42360679 is the first prime found in the decimal expansion of (Golden Ratio)^3, A098317.
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MAPLE
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Digits := 200:for n from 1 to 50 do: n0 := evalf(((sqrt(5)+1)/2)^n): for p from 1 to 100 while (type(trunc(10^p*n0), prime)= false) do:od: n2:= trunc(10^p*n0): print (n2): od:
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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