OFFSET
1,1
COMMENTS
Or, the same, diminished on 1 the sum of Fermi-Dirac divisors of the number Product_{i=1..n} A050376(i). Note that the sequence of the first differences 2, 9, 48, 300, ... lists sums of all numbers such that the maximal A050376-factor in their Fermi-Dirac representation is A050376(n). Note also that the average of numbers n >= 2 with A050376-factors not exceeding A050376(n) is a(n)/(2^n-1). Thus the sequence of such averages begins 2, 11/3, 59/7, 359/15, ...
Prime terms are 2, 11, 59, 359, 2879, 345599, 4838399, ...
LINKS
Peter J. C. Moses, Table of n, a(n) for n = 1..100
FORMULA
a(n) = -1 + Product_{i=1..n} (A050376(i) + 1).
EXAMPLE
a(3) = 2 + 3 + 2*3 = 11.
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev and Peter J. C. Moses, Sep 06 2013
STATUS
approved