A257658 Primes of the form A060735(k) +- 1, where A060735 lists multiples of primorials (A002110) less than the next larger primorial.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 59, 61, 89, 149, 151, 179, 181, 211, 419, 421, 631, 839, 1049, 1051, 1259, 1471, 1889, 2099, 2309, 2311, 4621, 9239, 9241, 11549, 11551, 13859, 18481, 20789, 23099, 25409, 25411, 30029, 90089, 120121, 150151, 180179, 180181

Offset

1,1

Comments

After a(9), all terms are congruent to +-1 (mod 30).

More generally, for any primorial P (cf. A002110), all terms >= P-1 are congruent to +/- 1 (mod P).- This sequence is essentially the same as A087715. - M. F. Hasler, Jul 27 2015

Links

James M. McCanney and Robert G. Wilson v, Table of n, a(n) for n = 1..1013

Formula

Primes among the numbers produced from A060735 +/- 1.

Example

149 & 151 are in the sequence because they are primes +-1 from A060735(12) = 150. A term does not have to be a twin prime; those are found in A087732.

Mathematica

f[n_] := Range[Prime[n + 1] - 1] Times @@ Prime@ Range@ n; Select[ Union@ Flatten@ Join[ Array[f, 6] - 1, Array[f, 7, 0] + 1], PrimeQ@# &]

Crossrefs

Cf. A060735, A087732, A002110.

Essentially the same as A087715.

Sequence in context: A268109 A283225 A100724 * A182231 A100110 A095323

Adjacent sequences: A257655 A257656 A257657 * A257659 A257660 A257661

Keyword

nonn

Author

James M. McCanney and Robert G. Wilson v, Jul 26 2015

Status

approved