A067199 Integers k such that k*28*c + 1 is prime for c = 1, 2, 4, 7 and 14.

2136, 2211, 4071, 5106, 5430, 9000, 10656, 17655, 18315, 20220, 20805, 21381, 22356, 22920, 23025, 29616, 37050, 39261, 45795, 49920, 55686, 60435, 62205, 64380, 79356, 81345, 91455, 94800, 95910, 96285, 105336, 108585, 111885, 118626

Offset

1,1

Comments

The product of the 5 primes is a Carmichael number. 28=1+2+4+7+14.

References

H. Davenport, The Higher Arithmetic. Cambridge Univ. Press, 7th ed., 1999, exercise 8.4.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

2136 results in Carmichael number 599966117492747584686619009.

Mathematica

aQ[n_] := AllTrue[{1, 2, 4, 7, 14}, PrimeQ[28 * n * # + 1] &]; Select[Range[10^5], aQ] (* Amiram Eldar, Sep 19 2019 *)

Crossrefs

Cf. A002997, A046025 (based on 6 instead of 28, exercise 8.3 in Davenport), A112428.

Sequence in context: A260068 A237070 A157768 * A064249 A206007 A233229

Adjacent sequences: A067196 A067197 A067198 * A067200 A067201 A067202

Keyword

nonn,easy

Author

Frank Ellermann, Feb 19 2002

Extensions

Offset corrected by Amiram Eldar, Sep 19 2019

Status

approved