A077317 a(n) is the n-th prime == 1 (mod n).

2, 5, 19, 29, 71, 43, 211, 193, 271, 191, 661, 277, 937, 463, 691, 769, 1531, 613, 2357, 1021, 1723, 1409, 3313, 1609, 3701, 2029, 3187, 2437, 6961, 1741, 7193, 3617, 4951, 3877, 7001, 3169, 10657, 6271, 7879, 5521, 13613, 3823, 15137, 7349, 9091, 7499

Offset: 1

Author

Amarnath Murthy, Nov 04 2002, Jul 23 2005 (submitted incorrectly on two separate occasions; each time it has had to be corrected)

Keywords

• nonn

Comments

a(n) is the n-th prime in the arithmetic progression with first term 1 and common difference n.

Main diagonal of A077316.

Examples

			a(5) = 71, the fifth prime in the sequence 1, 6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61, 66, 71, ...
		

Links

• Zak Seidov, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A034694, A077316, A077318, A077319, A093871.

Programs

Maple

a:=proc(n) local N, B, j: N:=[seq(n*x+1,x=0..500)]: B:={}: for j from 1 to nops(N) do if isprime(N[j])=true then B:=B union {N[j]} else fi od: B[n]: end: seq(a(n),n=1..55); # Emeric Deutsch, Sep 03 2005

Mathematica

Module[{nn=50,prs=Prime[Range[3000]]},Join[{2},Table[Select[prs,Mod[#,n] == 1&][[n]],{n,2,nn}]]] (* Harvey P. Dale, Nov 13 2020 *)

Extensions

Edited, corrected and extended by Emeric Deutsch, Sep 03 2005 and by Franklin T. Adams-Watters, Aug 29 2006

Edited by N. J. A. Sloane, Aug 23 2008 at the suggestion of R. J. Mathar