OFFSET
1,2
COMMENTS
a(n+1) is the (n+2)-th odd sum of two consecutive nonnegative nonprimes.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..2000
FORMULA
a(n+1) = A166685(n+2).
EXAMPLE
0 is a term because neither 0-1=-1 nor 0+1=1 is prime or semiprime.
MAPLE
isA001358 := proc(n) numtheory[bigomega](n) = 2 ; end proc: for n from 0 to 400 do if isA001358(n+1) or isA001358(n-1) or isprime(n+1) or isprime(n-1) then ; else printf("%d, ", n) ; end if; end do: # R. J. Mathar, Apr 20 2010
MATHEMATICA
Join[{0}, Flatten[Position[Partition[Table[If[PrimeQ[n]||PrimeOmega[n] == 2, 1, 0], {n, 250}], 3, 1], _?(#[[1]]==#[[3]]==0&), {1}, Heads -> False]]+ 1] (* Harvey P. Dale, Oct 27 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Apr 18 2010
EXTENSIONS
Entries checked by R. J. Mathar, Apr 20 2010
STATUS
approved