OFFSET
1,1
COMMENTS
Not currently known to be an infinite sequence.
Based on b-file of Giovanni Resta, the smallest value of a(n) such that a(n+1) - a(n) = 2 is 76156. - Altug Alkan, Aug 08 2017
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..342 (terms <= 10^5)
MATHEMATICA
g[w_] := FromDigits[Join @@ w, 2]; bp[1] = {1}; bp[n_] := Block[{b, r, h = Floor[n/2]}, Sort@ Flatten@ Table[b = IntegerDigits[k, 2, h]; r = Reverse@b; If[OddQ@n, g /@ {{b, {0}, r}, {b, {1}, r}}, g@{b, r}], {k, 2^h/2, 2^h - 1}]]; pp = Sort@Flatten[Table[bp[h], {h, 32}]]; T = Range[50000] * 0; i = 0; While[i < Length[pp] - 1, i++; j = i+1; While[j <= Length[pp] && (d = pp[[j]] - pp[[i]]) <= 10^5, T[[d/2]] = 1; j++]]; 2 Flatten[Position[T, 0]] (* Giovanni Resta, Aug 08 2017 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jeffrey Shallit, Jul 29 2017
STATUS
approved