|
%I #22 Oct 08 2019 17:12:40
%S 1,0,2,0,0,3,1,0,4,0,0,0,5,1,1,0,6,2,0,0,7,3,1,0,8,0,0,0,0,9,1,1,1,0,
%T 10,2,2,0,0,11,3,3,1,0,12,4,0,0,0,13,5,1,1,0,14,6,2,0,0,15,7,3,1,0,16,
%U 0,0,0,0,0,17,1,1,1,1,0,18,2,2,2,0,0,19
%N Table read by rows: T(n, k) is n with the first k bits removed from its binary expansion and then converted back to decimal, for 0 <= k <= A070939(n).
%H Peter Kagey, <a href="/A309577/b309577.txt">Table of n, a(n) for n = 1..9987</a> (first 1000 rows)
%F T(n,0) = n and T(n, A070939(n)) = 0.
%e For n = 26 and k = 2, T(26, 2) = 2 because 26 = 11010_2, and removing the first two bits leaves 010_2 = 2.
%e Table begins:
%e n\k| 0 1 2 3 4
%e ---+-----------
%e 1 | 1 0
%e 2 | 2 0 0
%e 3 | 3 1 0
%e 4 | 4 0 0 0
%e 5 | 5 1 1 0
%e 6 | 6 2 0 0
%e 7 | 7 3 1 0
%e 8 | 8 0 0 0 0
%e 9 | 9 1 1 1 0
%t T[n_, k_] := BitAnd[n, 2^k-1]; Table[T[n, k], {n, 1, 20}, {k, BitLength[n], 0, -1}] // Flatten (* _Amiram Eldar_, Aug 09 2019 *)
%o (Ruby)
%o def t(n,k); n & (1 << n.bit_length - k) - 1 end
%Y Cf. A070939, A309576.
%K nonn,tabf,base
%O 1,3
%A _Peter Kagey_, Aug 08 2019
|
