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A368619
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a(n) is the n-digit denominator of the fraction h/k with h and k coprime palindrome positive integers at which abs(h/k-e) is minimal.
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5
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1, 4, 323, 939, 14341, 61716, 1621261, 9192919, 324707423, 509838905, 30546664503, 59359795395, 3329737379233, 9164547454619
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OFFSET
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1,2
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COMMENTS
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a(3) = 323 corresponds to the denominator of A368617.
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LINKS
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EXAMPLE
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n fraction approximated value
- ------------------- ------------------
1 3/1 3
2 11/4 2.75
3 878/323 2.7182662538699...
4 2552/939 2.7177848775292...
5 38983/14341 2.7182902168607...
6 167761/61716 2.7182740294251...
7 4407044/1621261 2.7182816338640...
8 24988942/9192919 2.7182815382143...
9 882646288/324707423 2.7182818299783...
...
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MATHEMATICA
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a[1]=1; a[n_]:=Module[{minim = Infinity}, h = Select[Range[10^(n - 1), 10^n - 1], PalindromeQ]; lh = Length[h]; For[i = 1, i <= lh, i++, k = Select[Range[Floor[Part[h, i]/E], Ceiling[Part[h, i]/E]], PalindromeQ]; lk = Length[k]; For[j = 1, j <= lk, j++, If[(dist = Abs[Part[h, i]/Part[k, j] - E]) < minim && GCD[Part[h, i], Part[k, j]] == 1, minim = dist; kmin = Part[k, j]]]]; kmin]; Array[a, 9]
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PROG
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(PARI) \\ See PARI program in Links
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CROSSREFS
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KEYWORD
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nonn,base,frac,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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