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a(n) = max k such that A261015(n,k) is not zero.
5

%I #29 Aug 02 2018 17:08:12

%S 1,3,4,5,5,7,8,9,9,9,11,11,13,15,16,17,17,17,17,19,19,19,21,21,23,23,

%T 23,27,29,31,32,33,33,33,33,33,35,35,35,35,37,37,37,39,39,39,39,41,41,

%U 43,43,45,45,45,47,47,47,47

%N a(n) = max k such that A261015(n,k) is not zero.

%t (* This program is not suitable to compute more than a dozen terms. *)

%t notVis[bits_] := For[i = 0, True, i++, If[SequencePosition[bits, IntegerDigits[i, 2]] == {}, Return[i]]];

%t T[n_, k_] := Select[Rest[IntegerDigits[#, 2]] & /@ Range[2^n, 2^(n+1) - 1], notVis[#] == k &] // Length;

%t a[n_] := Do[If[T[n, k] > 0, Return[k]], {k, 2^n - 1, 0, -1}];

%t Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 1, 12}] (* _Jean-François Alcover_, Aug 02 2018 *)

%o (Haskell)

%o a261017 = subtract 1 . length . a261019_row

%o -- _Reinhard Zumkeller_, Aug 18 2015

%Y Cf. A261019, A261015, A261016, A260273.

%K nonn,more

%O 1,2

%A _N. J. A. Sloane_, Aug 17 2015

%E a(5)-a(17) from _Alois P. Heinz_, Aug 17 2015

%E a(18)-a(25) from _Reinhard Zumkeller_, Aug 18 2015

%E a(26)-a(36) from _Alois P. Heinz_, Aug 19 2015

%E a(37)-a(58) from _Hiroaki Yamanouchi_, Aug 23 2015