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 A196274 Half of the gaps A067970 between odd nonprimes A014076. 6
 4, 3, 3, 2, 1, 3, 1, 2, 3, 2, 1, 2, 1, 3, 1, 2, 3, 1, 2, 2, 1, 2, 1, 1, 2, 3, 3, 2, 1, 1, 1, 1, 1, 2, 2, 1, 3, 1, 1, 1, 3, 1, 2, 1, 2, 2, 1, 2, 1, 3, 1, 1, 1, 3, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 3, 2, 1, 3, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 3, 1, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) < 4 for n > 1; a(A196276(a(n)) = 1; a(A196277(a(n)) > 1. [Reinhard Zumkeller, Sep 30 2011] Lengths of runs of equal terms in A025549. That sequence begins with: 1,1,1,1,3,3,3,45,45,45,..., that is 4 ones, 3 threes, 3 forty-fives, ... - Michel Marcus, Dec 02 2014 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = (A014076(n+1)-A014076(n))/2 = A067970(n)/2. EXAMPLE The smallest odd numbers which are not prime are 1, 9, 15, 21, 25, 27,... (sequence A014076). The gaps between these are: 8, 6, 6, 4, 2,... (sequence A067970), which are of course all even by construction, so it makes sense to divide all of them by 2, which yields this sequence: 4, 3, 3, 2, 1, ... MATHEMATICA With[{nn=401}, Differences[Complement[Range[1, nn, 2], Prime[Range[ PrimePi[ nn]]]]]/2] (* Harvey P. Dale, May 06 2012 *) PROG (PARI) L=1; forstep(n=3, 299, 2, isprime(n)&next; print1((n-L)/2", "); L=n) CROSSREFS Cf. A142723 for the decimal value of the associated continued fraction. Sequence in context: A177038 A019975 A327869 * A073871 A120927 A241180 Adjacent sequences:  A196271 A196272 A196273 * A196275 A196276 A196277 KEYWORD nonn AUTHOR M. F. Hasler, Sep 30 2011 EXTENSIONS More terms from Harvey P. Dale, May 06 2012 STATUS approved

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Last modified October 19 13:01 EDT 2019. Contains 328222 sequences. (Running on oeis4.)