[seqfan] Alternating runs of non-primes and primes

[Eric Angelini]

Hitting the same nail...

Runs of non-primes and primes are alterned in seq B; the size
of each run is given by B itself:

B=1,2,3,4,6,8,5,7,11,13,9,10,12,14,15,16,17,19,23,29,31,37,41,43,
  18,20,21,22,24,47,53,59,61,67,71,73,25,26,27,28,30,32,33,34,35,36,38,...

Example:

B=1,2,3,4,6,8,5,7,11,13,9,10,12,14,15,16,17,19,23,29,31,37,41,43,
  . p p . . . p p  p  p .  .  .  .  .  .  p  p  p  p  p  p  p  p
  1  2    3       4             6                   8

B is a permutation of the natural numbers and B is not A083197:

http://www.research.att.com/~njas/sequences/A083197
"Triangular array, read by rows, where if n is odd the n-th row consists 
 of n least unused non-primes, while if n is even the n-th row consists
 of the n least unused primes."

Best,
É.