login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Irregular table T(n, k), n > 0, k = 1..A353292(n), read by rows: the n-th row contains in ascending order the distinct positive integers k <= n that have at least one common 1-bit with n.
3

%I #14 Jan 05 2024 13:43:00

%S 1,2,1,2,3,4,1,3,4,5,2,3,4,5,6,1,2,3,4,5,6,7,8,1,3,5,7,8,9,2,3,6,7,8,

%T 9,10,1,2,3,5,6,7,8,9,10,11,4,5,6,7,8,9,10,11,12,1,3,4,5,6,7,8,9,10,

%U 11,12,13,2,3,4,5,6,7,8,9,10,11,12,13,14

%N Irregular table T(n, k), n > 0, k = 1..A353292(n), read by rows: the n-th row contains in ascending order the distinct positive integers k <= n that have at least one common 1-bit with n.

%C See A352938 for the other k's.

%H Rémy Sigrist, <a href="/A353293/b353293.txt">Table of n, a(n) for n = 1..7163</a> (rows for n = 1..128 flattened)

%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>

%F T(n, 1) = A006519(n).

%F T(n, A353292(n)) = n.

%e Irregular table T(n, k) begins:

%e 1: [1]

%e 2: [2]

%e 3: [1, 2, 3]

%e 4: [4]

%e 5: [1, 3, 4, 5]

%e 6: [2, 3, 4, 5, 6]

%e 7: [1, 2, 3, 4, 5, 6, 7]

%e 8: [8]

%e 9: [1, 3, 5, 7, 8, 9]

%e 10: [2, 3, 6, 7, 8, 9, 10]

%e 11: [1, 2, 3, 5, 6, 7, 8, 9, 10, 11]

%e 12: [4, 5, 6, 7, 8, 9, 10, 11, 12]

%e 13: [1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]

%e 14: [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]

%e 15: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

%o (PARI) row(n) = select (k -> bitand(n, k), [1..n])

%Y Cf. A006519, A352938, A353292 (row lengths).

%K nonn,tabf,look,base

%O 1,2

%A _Rémy Sigrist_, Apr 09 2022