A084755 Let the sequence s_n be defined by s_n(1) = n+1 and for k > 1, s_n(k) = k*s_n(k-1)+1. Then a(n) is the first prime in the sequence s_n.

2, 3, 113, 5, 13, 7, 17, 19, 257, 11, 9157, 13, 29, 31, 401, 17, 37, 19, 41, 43, 82440101, 23, 593, 617, 53, 1117601, 71222359652296203545715260298095475932840563720928496792310817334884559392569395657640073370291521

Offset

1,1

Comments

For n = 10r+1, a(n) >= s_n(6).

Links

Table of n, a(n) for n=1..27.

Example

a(3) = 113: 3+1 = 4 is composite, 2*4+1 = 9 is composite, 3*9+1 = 28 is composite, 4*28+1 = 113 is prime.

Prog

(MATLAB) s = n + 1; k = 2; while (~isprime(s)) s = k*s + 1; k = k + 1; end a = s

Crossrefs

Sequence in context: A117700 A356789 A371023 * A215238 A356787 A371146

Adjacent sequences: A084752 A084753 A084754 * A084756 A084757 A084758

Keyword

nonn,hard

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 16 2003

Extensions

Edited and extended by David Wasserman, Sep 09 2003

One more term from David Wasserman, Jan 05 2005

Status

approved