A114147 Self-describing sequence : 1 prime between two nonprimes, then 2 primes between two nonprimes, then 4 primes, then 5, then 7, etc. The quantity of primes in each run is given by the sequence itself. (Sequence is strictly increasing and the smallest next available nonprime is used when needed).

1, 2, 4, 5, 7, 8, 11, 13, 17, 19, 20, 23, 29, 31, 37, 41, 42, 43, 47, 53, 59, 61, 67, 71, 72, 73, 79, 83, 89, 97, 101, 103, 107, 108, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 168, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 240, 241

Offset: 1

Author

Eric Angelini and Alexandre Wajnberg

Keywords

• base
• easy
• nonn

Examples

			Runs of primes are between brackets:
1,(2),4,(5,7),8,(11,13,17,19),20,(23,29,31,37,41),42,(43,47,53,59,61,67,71)
.^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
1 prime 2 pr. 4 primes 5 primes 7 primes (etc.) = the sequence itself
		

Programs

PARI

{m=10;k=1;v=[k];for(j=1,m,for(count=1,v[j],k=nextprime(k+1);v=concat(v,k)); while(isprime(k),k++);v=concat(v,k));for(n=1,#v,print1(v[n],","))} \\ Klaus Brockhaus