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A154555 Primes p such that m=(p-1)/2 is the least number such that p divides m!+1. 2
7, 11, 19, 43, 47, 127, 131, 163, 179, 191, 199, 263, 347, 367, 419, 431, 443, 491, 503, 523, 571, 619, 691, 727, 743, 787, 839, 863, 1051, 1087, 1091, 1123, 1291, 1319, 1367, 1451, 1487, 1499, 1571, 1579, 1583, 1667, 1723, 1783, 1823, 1931, 1951, 2003, 2039 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The graph of A073944 shows two prominent curves. This sequence gives the primes on the lower curve. Primes on the upper curve are in sequence A154554.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

MATHEMATICA

Rest[Reap[Do[p=Prime[i]; f=1; m=1; While[f=Mod[f*m, p]; f+1<p, m++ ]; If[m==(p-1)/2, Sow[p]], {i, 400}]]][[1, 1]]

CROSSREFS

Sequence in context: A038984 A165549 A055939 * A285016 A162857 A307965

Adjacent sequences:  A154552 A154553 A154554 * A154556 A154557 A154558

KEYWORD

nonn

AUTHOR

T. D. Noe, Jan 12 2009

STATUS

approved

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Last modified February 23 21:20 EST 2020. Contains 332195 sequences. (Running on oeis4.)