A364844 a(n) is the n-digit numerator of the fraction h/k with h and k coprime palindrome positive integers at which abs(h/k-Pi) is minimal.

3, 22, 474, 1551, 36163, 292292, 7327237, 31311313

Offset

1,1

Comments

a(2) = 22 corresponds to the numerator of A068028.

Links

Table of n, a(n) for n=1..8.

Index entries for sequences related to the number Pi

Example

  n              fraction    approximated value
  -   -------------------    ------------------
  1                     3    3
  2                  22/7    3.1428571428571...
  3               474/151    3.1390728476821...
  4              1551/494    3.1396761133603...
  5           36163/11511    3.1416036834332...
  6          292292/93039    3.1416072829673...
  7       7327237/2332332    3.1415926206046...
  8      31311313/9966699    3.1415931192464...
  ...

Mathematica

nmax = 8; a = {3}; hmin = kmin = 0; For[n = 2, n <= nmax, n++, minim = Infinity; h = Select[Range[10^(n - 1), 10^n - 1], PalindromeQ]; k = Select[Range[10^(n - 2), 10^n - 1], PalindromeQ]; lh = Length[h]; lk = Length[k]; For[i = 1, i <= lh, i++, For[j = 1, j <= lk, j++, If[(dist = Abs[Part[h, i]/Part[k, j] - Pi]) < minim && GCD[Part[h, i], Part[k, j]] == 1, minim = dist; hmin = Part[h, i]]]]; AppendTo[a, hmin]]; a

Crossrefs

Cf. A000796, A002113, A068028, A070252, A364845 (denominator), A364846.

Cf. A355622, A355623.

Sequence in context: A196734 A271849 A271850 * A156512 A119770 A272659

Adjacent sequences: A364841 A364842 A364843 * A364845 A364846 A364847

Keyword

nonn,base,frac,more

Author

Stefano Spezia, Aug 10 2023

Status

approved