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 A227984 Triangle T(n,k), read by rows: T(n,k) is the numerator of (1-2^(n-k+1))/(1-2^(k+1)). 2
 1, 3, 1, 7, 1, 1, 15, 7, 3, 1, 31, 5, 1, 1, 1, 63, 31, 15, 7, 3, 1, 127, 21, 31, 1, 7, 1, 1, 255, 127, 9, 31, 15, 1, 3, 1, 511, 85, 127, 21, 1, 5, 7, 1, 1, 1023, 511, 255, 127, 63, 31, 15, 7, 3, 1, 2047, 341, 73, 17, 127, 1, 31, 1, 1, 1, 1, 4095, 2047, 1023 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The denominators are given in A228035. The first column is A000225, the second column is A213243, and the third column is A213245. LINKS Vincenzo Librandi, Rows n = 0..100, flattened EXAMPLE Triangle begins: 1; 3,     1; 7,     1,  1; 15,    7,  3,    1; 31,    5,  1,    1,  1; 63,   31,  15,   7,  3,  1; 127,  21,  31,   1,  7,  1,  1; 255,  127,  9,   31, 15, 1,  3,  1; 511,  85,  127,  21, 1,  5,  7,  1, 1; 1023, 511, 255, 127, 63, 31, 15, 7, 3, 1; 2047, 341, 73,   17, 127, 1, 31, 1, 1, 1, 1; etc. MATHEMATICA a[n_, k_] := Numerator[(1 - 2^(n - k + 1))/(1 - 2^(k + 1))]; Table[a[n, k], {n, 0, 11}, {k, 0, n}] // Flatten PROG (MAGMA) [Numerator((1-2^(n-k+1))/(1-2^(k+1))): k in [0..n], n in [0..11]]; CROSSREFS Cf. A000225, A213243, A213245, A228035. Sequence in context: A097862 A097612 A136011 * A021991 A112132 A053381 Adjacent sequences:  A227981 A227982 A227983 * A227985 A227986 A227987 KEYWORD nonn,tabl,frac AUTHOR Vincenzo Librandi, Aug 12 2013 STATUS approved

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Last modified October 19 22:28 EDT 2018. Contains 316378 sequences. (Running on oeis4.)