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 A013942 Triangle of numbers T(n,k) = floor(2n/k), k=1..2n, read by rows. 7
 2, 1, 4, 2, 1, 1, 6, 3, 2, 1, 1, 1, 8, 4, 2, 2, 1, 1, 1, 1, 10, 5, 3, 2, 2, 1, 1, 1, 1, 1, 12, 6, 4, 3, 2, 2, 1, 1, 1, 1, 1, 1, 14, 7, 4, 3, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 16, 8, 5, 4, 3, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 18, 9, 6, 4, 3, 3, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 20, 10, 6, 5, 4, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) is also the leading term in period of continued fraction for n-th nonsquare. Row A026741(n) contains n and all rows with a smaller row number do not contain n. - Reinhard Zumkeller, Jun 04 2013 LINKS Reinhard Zumkeller, Rows n = 1..100 of table, flattened FORMULA T(n,k) = floor(2n/k), k=1,...,2n. T(n,k) = [1/{sqrt(k+n^2)}], k=1,2,...,2n, {}=fractional part, []=floor. EXAMPLE First four rows: 2 1 4 2 1 1 6 3 2 1 1 1 8 4 2 2 1 1 1 1 MATHEMATICA f[n_, h_]:=FractionalPart[(n^2+h)^(1/2)]; g[n_, h_]:=Floor[1/f[n, h]]; TableForm[Table[g[n, h], {n, 1, 13}, {h, 1, 2n}]] PROG (Haskell) a013942 n k = a013942_tabf !! (n-1) !! (k-1) a013942_row n = map (div (n * 2)) [1 .. 2 * n] a013942_tabf = map a013942_row [1 ..] -- Reinhard Zumkeller, Jun 04 2013 (PARI) T(n, k) = 2*n\k; tabf(nn) = for (n=1, nn, for (k=1, 2*n, print1(T(n, k), ", ")); print()); \\ Michel Marcus, Sep 30 2016 CROSSREFS Cf. A010766. Cf. A005843 (row lengths and left edge), A062550 (row sums). Sequence in context: A330086 A290935 A031424 * A187816 A088423 A006839 Adjacent sequences:  A013939 A013940 A013941 * A013943 A013944 A013945 KEYWORD nonn,tabf,easy,nice AUTHOR EXTENSIONS Keyword tabl replaced by tabf and missing a(90)=1 inserted by Reinhard Zumkeller, Jun 04 2013 STATUS approved

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Last modified June 16 13:44 EDT 2021. Contains 345057 sequences. (Running on oeis4.)