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A077317
a(n) is the n-th prime == 1 (mod n).
5
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
1,1
COMMENTS
a(n) is the n-th prime in the arithmetic progression with first term 1 and common difference n.
Main diagonal of A077316.
EXAMPLE
a(5) = 71, the fifth prime in the sequence 1, 6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61, 66, 71, ...
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 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Nov 04 2002, Jul 23 2005 (submitted incorrectly on two separate occasions; each time it has had to be corrected)
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
STATUS
approved