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 A143537 Triangle read by rows: T(n,k) = number of primes in the interval [k..n], n >= 1, 1 <= k <= n. 1
 0, 1, 1, 2, 2, 1, 2, 2, 1, 0, 3, 3, 2, 1, 1, 3, 3, 2, 1, 1, 0, 4, 4, 3, 2, 2, 1, 1, 4, 4, 3, 2, 2, 1, 1, 0, 4, 4, 3, 2, 2, 1, 1, 0, 0, 4, 4, 3, 2, 2, 1, 1, 0, 0, 0, 5, 5, 4, 3, 3, 2, 2, 1, 1, 1, 1, 5, 5, 4, 3, 3, 2, 2, 1, 1, 1, 1, 0, 6, 6, 5, 4, 4, 3, 3, 2, 2, 2, 2, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Old name: triangle read by rows, A000012 * A143536, 1<=k<=n. LINKS FORMULA T(n,k) = pi(n) - pi(k-1), where pi = A000720. - Ilya Gutkovskiy, Mar 19 2020 EXAMPLE Triangle T(n,k) begins: n\k 1  2  3  4  5  6  7  8 ... 1:  0; 2:  1, 1; 3:  2, 2, 1; 4:  2, 2, 1, 0; 5:  3, 3, 2, 1, 1; 6:  3, 3, 2, 1, 1, 0; 7:  4, 4, 3, 2, 2, 1, 1; 8:  4, 4, 3, 2, 2, 1, 1, 0; ... CROSSREFS Row sums are A034387. Column k=1 gives A000720. Main diagonal gives A010051. T(2n,n) gives A035250. Cf. A143536. Sequence in context: A285930 A300480 A342870 * A125916 A283468 A100244 Adjacent sequences:  A143534 A143535 A143536 * A143538 A143539 A143540 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Aug 23 2008 EXTENSIONS New name and corrected by Ilya Gutkovskiy, Mar 19 2020 STATUS approved

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Last modified May 15 06:46 EDT 2021. Contains 343909 sequences. (Running on oeis4.)