1,2

It appears that there are many more values in this sequence than in A068791, Ulam numbers n such that 2*n is also an Ulam number.

Table of n, a(n) for n=1..46.

Cf. A068791.

Sequence in context: A265107 A217631 A046209 * A273348 A198951 A078774

Adjacent sequences: A285882 A285883 A285884 * A285886 A285887 A285888

nonn

Enrique Navarrete, Apr 27 2017

approved