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 A280926 Least k such that the first n digits of the decimal expansion of the ratio of the perimeter of a regular k-gon to its diameter match those of Pi. 0
 5, 7, 29, 47, 119, 699, 1407, 4911, 18971, 46803, 119951, 363209 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS By definition, the diameter of a regular k-gon is the length of its longest diagonal. LINKS EXAMPLE This ratio for a regular 7-gon (heptagon) is 3.115293... (A280533), where 3.1 equals the first two digits of Pi's decimal expansion. Because the first two digits are not 3.1 for k < 7, a(2) = 7. CROSSREFS Cf. A000796, A280533. Sequence in context: A018776 A104683 A153121 * A070153 A293943 A171619 Adjacent sequences:  A280923 A280924 A280925 * A280927 A280928 A280929 KEYWORD nonn,base,more AUTHOR Rick L. Shepherd, Jan 10 2017 STATUS approved

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Last modified February 29 02:05 EST 2020. Contains 332353 sequences. (Running on oeis4.)