cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A359887 Square array A(n, k), n, k > 0, read by antidiagonals; A(n, k) is the numerator of the unique rational q such that for any m, floor(2^m/n) AND floor(2^m/k) = floor(q*2^m) (where AND denotes the bitwise AND operator); see A359888 for the denominators.

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%I A359887 #8 Jan 19 2023 11:10:12
%S A359887 1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,1,1,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,
%T A359887 0,0,0,0,1,0,1,0,1,0,0,0,0,0,0,2,2,0,0,0,0,0,0,5,0,57,1,57,0,5,0,0,0,
%U A359887 0,1,0,1,8,8,1,0,1,0,0,0,0,85,0,37,1,1,1,37,0,85,0,0
%N A359887 Square array A(n, k), n, k > 0, read by antidiagonals; A(n, k) is the numerator of the unique rational q such that for any m, floor(2^m/n) AND floor(2^m/k) = floor(q*2^m) (where AND denotes the bitwise AND operator); see A359888 for the denominators.
%C A359887 A(n, k)/A359888(n, k) can be interpreted as (1/n) AND (1/k) (assuming that inverses of powers of 2 have terminating binary expansions).
%H A359887 Rémy Sigrist, <a href="/A359887/a359887.gp.txt">PARI program</a>
%F A359887 A(n, k) = A(k, n).
%F A359887 A(n, n) = 1.
%F A359887 A(n, 2*n) = 0 iff n belongs to A300630.
%F A359887 A(A306231(n), A306231(n+1)) = 0.
%F A359887 A(n, A359806(n)) = 0.
%e A359887 Square array A(n, k) begins:
%e A359887   n\k | 1  2   3  4    5  6     7  8       9   10      11  12
%e A359887   ----+------------------------------------------------------
%e A359887     1 | 1  0   0  0    0  0     0  0       0    0       0   0
%e A359887     2 | 0  1   0  0    0  0     0  0       0    0       0   0
%e A359887     3 | 0  0   1  1    1  0     1  0       5    1      85   1
%e A359887     4 | 0  0   1  1    0  0     0  0       0    0       0   0
%e A359887     5 | 0  0   1  0    1  2    57  1      37    1     837   1
%e A359887     6 | 0  0   0  0    2  1     8  1       2    1       8   0
%e A359887     7 | 0  0   1  0   57  8     1  1       1    1    1195   1
%e A359887     8 | 0  0   0  0    1  1     1  1       0    0       0   0
%e A359887     9 | 0  0   5  0   37  2     1  0       1   11  256687   5
%e A359887    10 | 0  0   1  0    1  1     1  0      11    1     749   1
%e A359887    11 | 0  0  85  0  837  8  1195  0  256687  749       1  85
%e A359887    12 | 0  0   1  0    1  0     1  0       5    1      85   1
%o A359887 (PARI) See Links section.
%Y A359887 Cf. A300630, A306231, A359806, A359888 (denominators).
%K A359887 nonn,base,frac,tabf
%O A359887 1,50
%A A359887 _Rémy Sigrist_, Jan 17 2023