A358757 Numbers k such that the smallest prime that does not divide them is of the form 6m-1.

6, 12, 18, 24, 36, 42, 48, 54, 66, 72, 78, 84, 96, 102, 108, 114, 126, 132, 138, 144, 156, 162, 168, 174, 186, 192, 198, 204, 210, 216, 222, 228, 234, 246, 252, 258, 264, 276, 282, 288, 294, 306, 312, 318, 324, 336, 342, 348, 354, 366, 372, 378, 384, 396, 402, 408, 414, 420, 426, 432, 438, 444, 456

Offset

1,1

Comments

Numbers k such that A053669(k) is in A007528.

The asymptotic density of this sequence is Sum_{p prime, p == 5 (mod 6)} ((p-1)/(Product_{q prime, q <= p} q)) = 0.1376937818... . - Amiram Eldar, Dec 04 2022

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

filter:= proc(n) local p;
 p:= 3;
 do
   p:= nextprime(p);
   if n mod p <> 0 then return (p mod 6 = 5) fi
 od
end proc:
select(filter, [seq(i, i=6..1000, 6)]); # Robert Israel, Dec 04 2023

Mathematica

f[n_] := Module[{p = 2}, While[Divisible[n, p], p = NextPrime[p]]; p]; Select[Range[500], Mod[f[#], 6] == 5 &] (* Amiram Eldar, Dec 04 2022 *)

Prog

(PARI) isA358757(n) = A358755(n);

Crossrefs

Cf. A007528, A053669, A358755 (characteristic function), A358756.

Differs from A353530 for the first time at n=29, where a(29) = 210, which is not present in A353530.

Sequence in context: A033018 A189781 A182302 * A353530 A244193 A329878

Adjacent sequences: A358754 A358755 A358756 * A358758 A358759 A358760

Keyword

nonn

Author

Antti Karttunen, Dec 03 2022

Status

approved