OFFSET
1,1
COMMENTS
The asymptotic density of this sequence is 1/2 (Erdős, 1936). - Amiram Eldar, Mar 19 2021
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
Paul Erdős, On a problem of Chowla and some related problems, Mathematical Proceedings of the Cambridge Philosophical Society, Vol. 32, No. 4 (1936), pp. 530-540; alternative link.
MAPLE
with(numtheory): seq( `if`((sigma(i) > sigma(i+1)), i, print( )), i=1..139);
MATHEMATICA
Select[Range[150], DivisorSigma[1, #] > DivisorSigma[1, # + 1] &] (* Carl Najafi, Aug 16 2011 *)
PROG
(Haskell)
import Data.List (findIndices)
a053226 n = a053226_list !! (n-1)
a053226_list = map (+ 1) $ findIndices (< 0) a053222_list
-- Reinhard Zumkeller, Oct 16 2011
(PARI) is(n)=sigma(n)>sigma(n+1) \\ Charles R Greathouse IV, Mar 09 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Asher Auel, Jan 06 2000
STATUS
approved