A331533 - OEIS

A331533

Irregular table read by rows; for n >= 0, the n-th row corresponds to the nonnegative integers k such that (n^2) AND (k^2) = k^2, in ascending order (where AND denotes the bitwise AND operator).

%I #12 Jan 20 2020 12:54:39

%S 0,0,1,0,2,0,1,3,0,4,0,1,3,4,5,0,2,6,0,1,4,7,0,8,0,1,4,8,9,0,2,6,8,10,

%T 0,1,3,4,5,7,8,9,11,0,4,12,0,1,3,13,0,2,8,14,0,1,8,15,0,16,0,1,16,17,

%U 0,2,8,16,18,0,1,3,8,16,17,19,0,4,12,16,20

%N Irregular table read by rows; for n >= 0, the n-th row corresponds to the nonnegative integers k such that (n^2) AND (k^2) = k^2, in ascending order (where AND denotes the bitwise AND operator).

%C The n-th row has A331532(n) terms, leading term 0 and last term n.

%H Rémy Sigrist, <a href="/A331533/b331533.txt">Table of n, a(n) for n = 0..7118</a> (rows for n = 0..512)

%e Table begins:

%e 0;

%e 0, 1;

%e 0, 2;

%e 0, 1, 3;

%e 0, 4;

%e 0, 1, 3, 4, 5;

%e 0, 2, 6;

%e 0, 1, 4, 7;

%e 0, 8;

%e ...

%o (PARI) row(n) = select(k -> bitand(n^2, k^2)==k^2, [0..n])

%Y Cf. A295989, A331532 (row lengths).

%K nonn,tabf,base

%O 0,5

%A _Rémy Sigrist_, Jan 19 2020