OFFSET
1,2
COMMENTS
Using the Prime Number Theorem, Gica and Panaitopol show that the sequence contains infinitely many primes.
REFERENCES
A. Gica and L. Panaitopol, An application of the prime element theorem, Gazeta Matematica 21(100), No. 2 (2003), 113-115.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
EXAMPLE
The terms occur in disjoint blocks of decreasing consecutive numbers: 1; 2; 4, 3; 6, 5; 10, 9, 8; 16, 15, 14, 13; 26, 25, 24, 23, 22, 21, 20; . . .
MATHEMATICA
a[1] = 1; a[n_] := a[n] = If[a[n-1] <= n-1, 2*a[n-1], a[n-1]-1]; Table[a[n], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Sondow, Jul 21 2011
STATUS
approved