login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A020203
Pseudoprimes to base 75.
1
74, 91, 133, 247, 259, 289, 427, 481, 703, 793, 1073, 1159, 1261, 1387, 1541, 1649, 1729, 1849, 1891, 2071, 2257, 2413, 2701, 2813, 2821, 3367, 3589, 4033, 4681, 4699, 4921, 5551, 5917, 6061, 6533, 6601, 6643, 7957, 8113, 8321, 8614, 8911, 9139, 9211
OFFSET
1,1
COMMENTS
Composite numbers n such that 75^(n-1) == 1 (mod n).
MATHEMATICA
base = 75; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n-1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)
CROSSREFS
Cf. A001567 (pseudoprimes to base 2).
Sequence in context: A095569 A305265 A055111 * A295158 A039484 A098516
KEYWORD
nonn
STATUS
approved