A175074 Nonprimes b with result 1 under iterations of {r mod (max prime p < r)} starting at r = b.

1, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 27, 30, 32, 34, 35, 38, 40, 42, 44, 46, 48, 50, 51, 54, 56, 57, 60, 62, 64, 65, 68, 70, 72, 74, 76, 77, 80, 82, 84, 86, 87, 90, 92, 93, 95, 98, 100, 102

Offset

1,2

Comments

Subsequence of A175071. Union of a(n) and A175073 is A175071.

Union of a(n) and A175073 is A175071. [From Jaroslav Krizek, Jan 30 2010]

Links

Table of n, a(n) for n=1..51.

Example

Iteration procedure for a(5) = 10: 10 mod 7 = 3, 3 mod 2 = 1.

Mathematica

np1Q[n_]:=!PrimeQ[n]&&MemberQ[NestWhileList[Mod[#, NextPrime[#, -1]]&, n, #>0&], 1]; Select[Range[150], np1Q] (* Harvey P. Dale, Jun 27 2020 *)

Crossrefs

Sequence in context: A330948 A324705 A032583 * A063127 A272651 A103517

Adjacent sequences: A175071 A175072 A175073 * A175075 A175076 A175077

Keyword

nonn

Author

Jaroslav Krizek, Jan 23 2010

Status

approved