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 A167707 The non-single or nonisolated numbers. The union of non-single (or nonisolated or twin) primes and non-single (or nonisolated) nonprimes. 19
 0, 1, 3, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 38, 39, 40, 41, 43, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS A167707 = A001097 U A164276. A167706 U A167707 = A001477. LINKS G. C. Greubel, Table of n, a(n) for n = 1..1000 FORMULA a(n) = n + n / log n + O(n / (log n)^2) by Brun's theorem. [Charles R Greathouse IV, Mar 15 2011] MAPLE isA001097 := proc(n) isprime(n) and (isprime(n+2) or isprime(n-2)) ; end proc: isA164276 := proc(n) not isprime(n) and ( not isprime(n+1) or not isprime(n-1) ) ; end proc: isA167707 := proc(n) isA001097(n) or isA164276(n) ; end proc: for n from 0 to 100 do if isA167707(n) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Mar 18 2010 MATHEMATICA Union[Select[Range[0, 300], !PrimeQ[#] && (! PrimeQ[# - 1] || ! PrimeQ[# + 1]) & ], Select[Prime[Range[300]], PrimeQ[# - 2] || PrimeQ[# + 2] &]] (* G. C. Greubel, Jul 07 2016 *) CROSSREFS Cf. A001097, A001477, A164276, A167706. Sequence in context: A217129 A336340 A100318 * A131903 A141114 A136443 Adjacent sequences: A167704 A167705 A167706 * A167708 A167709 A167710 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Nov 10 2009 STATUS approved

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Last modified March 5 09:09 EST 2024. Contains 370545 sequences. (Running on oeis4.)