A340351 Square array, read by descending antidiagonals, where row n gives all solutions k > 0 to A000120(k)=A000120(k*n), A000120 is the Hamming weight.

1, 2, 1, 3, 2, 3, 4, 3, 6, 1, 5, 4, 7, 2, 7, 6, 5, 12, 3, 14, 3, 7, 6, 14, 4, 15, 6, 7, 8, 7, 15, 5, 27, 7, 14, 1, 9, 8, 24, 6, 28, 12, 15, 2, 15, 10, 9, 28, 7, 30, 14, 19, 3, 30, 7, 11, 10, 30, 8, 31, 15, 28, 4, 31, 14, 3, 12, 11, 31, 9, 39, 24, 30, 5, 43, 15, 6, 3, 13, 12

Offset

1,2

Comments

Square array is read by descending antidiagonals, as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), etc.

Rows at positions 2^k are 1, 2, 3, ..., (A000027). Row 2n is equal to row n.

Values are different from those in A115872, because we use multiplication with carry here.

Links

Table of n, a(n) for n=1..80.

Example

Eight initial terms of rows 1 - 8 are listed below:
   1:  1,  2,  3,   4,   5,   6,   7,   8, ...
   2:  1,  2,  3,   4,   5,   6,   7,   8, ...
   3:  3,  6,  7,  12,  14,  15,  24,  28, ...
   4:  1,  2,  3,   4,   5,   6,   7,   8, ...
   5:  7, 14, 15,  27,  28,  30,  31,  39, ...
   6:  3,  6,  7,  12,  14,  15,  24,  28, ...
   7:  7, 14, 15,  19,  28,  30,  31,  37, ...
   8:  1,  2,  3,   4,   5,   6,   7,   8, ...
a(6,3) = 7 because: 7 in binary is 111 and 6*7 = 42 in binary is 101001, both have 3 bits set to 1.

Prog

(MATLAB)
function [a] = A340351(max_n)
    for n = 1:max_n
        m = 1;
        k = 1;
        while m < max_n
            c = length(find(bitget(k, 1:32)== 1));
            if c == length(find(bitget(n*k, 1:32)== 1))
                a(n, m) = k;
                m = m+1;
            end
            k = k +1;
        end
    end
end

Crossrefs

Cf. A000120, A292849 (1st column), A340069, A077459 (3rd row).

Sequence in context: A350013 A240450 A352129 * A115872 A133926 A144337

Adjacent sequences: A340348 A340349 A340350 * A340352 A340353 A340354

Keyword

nonn,base,tabl

Author

Thomas Scheuerle, Jan 05 2021

Status

approved