OFFSET
1,2
COMMENTS
The scaled values a(n)/2^n are (to nine decimal places) 0.5000000000, 1.500000000, 2.250000000, 2.875000000, 3.343750000, 3.765625000, 4.179687500, 4.601562500, 5.017578125, 5.416015625, 5.790527344, 6.141601562, 6.476806641, 6.798034668, 7.109558105, 7.416122437, 7.722358704, 8.028903961, 8.336341858, 8.644985199, 8.954413414, 9.264011145, 9.573415518, 9.881861508, 10.18858004, 10.49296834, 10.79449527, 11.09269635, 11.38722431, 11.67781548, 11.96431363, 12.24665452, ...
LINKS
Alois P. Heinz and Hiroaki Yamanouchi, Table of n, a(n) for n = 1..58 (a(1)-a(36) from Alois P. Heinz)
MATHEMATICA
(* This program is not suitable to compute more than a dozen terms. *)
notVis[bits_] := For[i = 0, True, i++, If[SequencePosition[bits, IntegerDigits[i, 2]] == {}, Return[i]]];
T[n_, k_] := Select[Rest[IntegerDigits[#, 2]] & /@ Range[2^n, 2^(n+1) - 1], notVis[#] == k &] // Length;
a[n_] := Sum[k*T[n, k], {k, 0, 2^n - 1}];
Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 1, 12}] (* Jean-François Alcover, Aug 02 2018 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Aug 16 2015
EXTENSIONS
a(5)-a(16) from Alois P. Heinz, Aug 17 2015
a(17)-a(25) from Reinhard Zumkeller, Aug 18 2015
a(26)-a(32) from Alois P. Heinz, Aug 19 2015
STATUS
approved