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.
%I A340351 #15 Mar 15 2022 20:58:39 %S A340351 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, %T A340351 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, %U A340351 8,31,15,28,4,31,14,3,12,11,31,9,39,24,30,5,43,15,6,3,13,12 %N 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. %C A340351 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. %C A340351 Rows at positions 2^k are 1, 2, 3, ..., (A000027). Row 2n is equal to row n. %C A340351 Values are different from those in A115872, because we use multiplication with carry here. %e A340351 Eight initial terms of rows 1 - 8 are listed below: %e A340351 1: 1, 2, 3, 4, 5, 6, 7, 8, ... %e A340351 2: 1, 2, 3, 4, 5, 6, 7, 8, ... %e A340351 3: 3, 6, 7, 12, 14, 15, 24, 28, ... %e A340351 4: 1, 2, 3, 4, 5, 6, 7, 8, ... %e A340351 5: 7, 14, 15, 27, 28, 30, 31, 39, ... %e A340351 6: 3, 6, 7, 12, 14, 15, 24, 28, ... %e A340351 7: 7, 14, 15, 19, 28, 30, 31, 37, ... %e A340351 8: 1, 2, 3, 4, 5, 6, 7, 8, ... %e A340351 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. %o A340351 (MATLAB) %o A340351 function [a] = A340351(max_n) %o A340351 for n = 1:max_n %o A340351 m = 1; %o A340351 k = 1; %o A340351 while m < max_n %o A340351 c = length(find(bitget(k,1:32)== 1)); %o A340351 if c == length(find(bitget(n*k,1:32)== 1)) %o A340351 a(n,m) = k; %o A340351 m = m+1; %o A340351 end %o A340351 k = k +1; %o A340351 end %o A340351 end %o A340351 end %Y A340351 Cf. A000120, A292849 (1st column), A340069, A077459 (3rd row). %K A340351 nonn,base,tabl %O A340351 1,2 %A A340351 _Thomas Scheuerle_, Jan 05 2021