OFFSET
1,2
COMMENTS
The odd noncomposite numbers. Also odd primes at the beginning of the 20th century. - Omar E. Pol, Mar 19 2008
Indices at which records occur in A002322. - Artur Jasinski, Apr 05 2008
Odd numbers n such that their largest divisor <= sqrt(n) equals 1. (See A161344). - Omar E. Pol, Aug 03 2009
All k for which cos((k-1)!*Pi/k) is negative. - Gerry Martens, Jun 01 2018
LINKS
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972, p. 870 [alternative scanned copy].
S. M. Losanitsch, Die Isomerie-Arten bei den Homologen der Paraffin-Reihe, Chem. Ber. 30 (1897), 1917-1926. (Annotated scanned copy)
FORMULA
a(n) = A000040(n) - A000007(n) = A000040(n) - ((-1)^A000040(n)+1)/2. - Juri-Stepan Gerasimov, Oct 25 2009
a(n) = A175524(n) for n <= 30. - Reinhard Zumkeller, Jul 12 2011
MATHEMATICA
a = {}; max = 0; Do[w = CarmichaelLambda[k]; If[w > max, AppendTo[a, k]; max = k], {k, 1, 200}]; a (* Artur Jasinski, Apr 05 2008 *)
Join[{1}, Prime[Range[2, 60]]] (* Harvey P. Dale, Apr 15 2019 *)
PROG
(PARI) prime(n)-(n==1) \\ Charles R Greathouse IV, Aug 26 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved