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A301983 Irregular triangle read by rows T(n, k), n >= 1 and 1 <= k <= A301977(n): T(n, k) is the k-th positive number whose binary digits appear in order but not necessarily as consecutive digits in the binary representation of n.

%I A301983 #14 Jan 26 2022 11:45:20
%S A301983 1,1,2,1,3,1,2,4,1,2,3,5,1,2,3,6,1,3,7,1,2,4,8,1,2,3,4,5,9,1,2,3,4,5,
%T A301983 6,10,1,2,3,5,7,11,1,2,3,4,6,12,1,2,3,5,6,7,13,1,2,3,6,7,14,1,3,7,15,
%U A301983 1,2,4,8,16,1,2,3,4,5,8,9,17,1,2,3,4,5,6
%N A301983 Irregular triangle read by rows T(n, k), n >= 1 and 1 <= k <= A301977(n): T(n, k) is the k-th positive number whose binary digits appear in order but not necessarily as consecutive digits in the binary representation of n.
%C A301983 This sequence has similarities with A119709 and A165416; there we consider consecutive digits, here not.
%H A301983 Rémy Sigrist, <a href="/A301983/b301983.txt">Rows n = 1..500 of triangle, flattened</a>
%H A301983 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A301983 T(n, 1) = 1.
%F A301983 T(n, A301977(n)) = n.
%F A301983 T(2^n, k) = 2^(k-1) for any n > 0 and k = 1..n+1.
%F A301983 T(2^n - 1, k) = 2^k - 1 for any n > 0 and k = 1..n.
%e A301983 Triangle begins:
%e A301983    1:    [1]
%e A301983    2:    [1, 2]
%e A301983    3:    [1, 3]
%e A301983    4:    [1, 2, 4]
%e A301983    5:    [1, 2, 3, 5]
%e A301983    6:    [1, 2, 3, 6]
%e A301983    7:    [1, 3, 7]
%e A301983    8:    [1, 2, 4, 8]
%e A301983    9:    [1, 2, 3, 4, 5, 9]
%e A301983   10:    [1, 2, 3, 4, 5, 6, 10]
%e A301983   11:    [1, 2, 3, 5, 7, 11]
%e A301983   12:    [1, 2, 3, 4, 6, 12]
%e A301983   13:    [1, 2, 3, 5, 6, 7, 13]
%e A301983   14:    [1, 2, 3, 6, 7, 14]
%e A301983   15:    [1, 3, 7, 15]
%e A301983   16:    [1, 2, 4, 8, 16]
%p A301983 b:= proc(n) option remember; `if`(n=0, {0},
%p A301983       map(x-> [x, 2*x+r][], b(iquo(n, 2, 'r'))))
%p A301983     end:
%p A301983 T:= n-> sort([(b(n) minus {0})[]])[]:
%p A301983 seq(T(n), n=1..20);  # _Alois P. Heinz_, Jan 26 2022
%o A301983 (PARI) T(n,k) = my (b=binary(n), s=Set(1)); for (i=2, #b, s = setunion(s, Set(apply(v -> 2*v+b[i], s)))); return (s[k])
%Y A301983 Cf. A119709, A165416, A301977 (row length).
%K A301983 nonn,base,tabf
%O A301983 1,3
%A A301983 _Rémy Sigrist_, Mar 30 2018