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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 February 23 03:34 EST 2018. Contains 299473 sequences. (Running on oeis4.)