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A175218
The third nonprimes after the primes.
0
8, 8, 9, 10, 15, 16, 21, 22, 26, 33, 34, 40, 45, 46, 50, 56, 63, 64, 70, 75, 76, 82, 86, 92, 100, 105, 106, 111, 112, 116, 130, 134, 141, 142, 153, 154, 160, 166, 170, 176, 183, 184, 195, 196, 201, 202, 214, 226, 231, 232, 236, 243, 244, 254, 260, 266, 273, 274
OFFSET
1,1
FORMULA
For n>2: a(n) = A000040(n) + 2 + A010051(A000040(n) + 2) + 1. - Reinhard Zumkeller, Mar 29 2010 [corrected by Georg Fischer, Oct 06 2024]
EXAMPLE
prime(49) = 227, prime(50) = 229, therefore (228=1st, 230=2nd nonprime), 231 = a(49). - Georg Fischer, Oct 06 2024
PROG
(PARI) a(n) = if(n<=2, 8, prime(n) + 2 + isprime(prime(n)+2) + 1) /* Georg Fischer, Oct 06 2024 */
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Mar 06 2010
EXTENSIONS
More terms from Reinhard Zumkeller, Mar 29 2010
a(49), a(52) and a(57) corrected by Georg Fischer, Oct 06 2024
STATUS
approved