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 A138553 Table read by rows: T(n,k) is the number of divisors of k that are <= n. 2
 1, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 3, 1, 3, 1, 3, 2, 2, 1, 4, 1, 2, 2, 3, 2, 3, 1, 3, 2, 3, 1, 4, 1, 2, 3, 3, 1, 3, 1, 4, 2, 2, 1, 4, 2, 2, 2, 3, 1, 4, 1, 3, 2, 2, 2, 4, 1, 2, 2, 4, 1, 3, 1, 3, 3, 2, 1, 4, 1, 3, 2, 3, 1, 3, 2, 3, 2, 2, 1, 5, 1, 2, 2, 3, 2, 4, 1, 3, 2, 3, 1, 5, 1, 2, 3, 3, 1, 4, 1, 4, 2, 2, 1, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Suggested by a question from Eric Desbiaux. The row lengths are the lengths before the pattern for n repeats. Antidiagonal sums A070824. [From Eric Desbiaux, Dec 10 2009] LINKS FORMULA T(n,k) = sum_{i|k, i<=n} 1. EXAMPLE The first few rows start: 1, [A000012] 1, 2, [A000034] 1, 2, 2, 2, 1, 3, [A083039] 1, 2, 2, 3, 1, 3, 1, 3, 2, 2, 1, 4, [A083040] PROG (PARI) lista(nrows) = {for (n=1, nrows, for (k=1, lcm(vector(n, i, i)), print1(sumdiv(k, d, d <=n), ", "); ); print(); ); } \\ Michel Marcus, Jun 19 2014 CROSSREFS Row lengths A003418, row sums A025529, frequencies in rows A096180. Cf. A243987 Sequence in context: A334507 A342462 A239140 * A069016 A211270 A071414 Adjacent sequences:  A138550 A138551 A138552 * A138554 A138555 A138556 KEYWORD easy,nonn,tabf AUTHOR Franklin T. Adams-Watters, Mar 24 2008 EXTENSIONS Definition corrected by Franklin T. Adams-Watters, Jun 19 2014 STATUS approved

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Last modified April 12 18:47 EDT 2021. Contains 342931 sequences. (Running on oeis4.)