A232846 a(n) is the length of the n-th chunk of nonprimes in this sequence, the chunks being separated by primes; lexicographically least such sequence (starting with a nonprime).

1, 2, 4, 6, 3, 8, 9, 10, 12, 5, 14, 15, 16, 18, 20, 21, 7, 22, 24, 25, 11, 26, 27, 28, 30, 32, 33, 34, 35, 13, 36, 38, 39, 40, 42, 44, 45, 46, 48, 17, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 19, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 23, 77, 78, 80, 81

Offset

1,2

Comments

This is a permutation of the positive integers. See A232805 for the variant starting with a prime.

Links

Table of n, a(n) for n=1..68.

M. F. Hasler, in reply to E. Angelini, Self-describing chunks of primes, SeqFan list, Nov 30 2013

Prog

(PARI) {N -> my(a=[1], c=1, i=1, p=1); while(#a<N, a=concat(a, p=nextprime(p+1)); for(j=1, a[i++], while(isprime(c++), ); a=concat(a, c)); a}

Crossrefs

Sequence in context: A089088 A251622 A073899 * A101543 A073900 A361629

Adjacent sequences: A232843 A232844 A232845 * A232847 A232848 A232849

Keyword

nonn

Author

M. F. Hasler, Nov 30 2013

Status

approved