A228541 Numbers having at least one prime factor of the form 30*k + 1.

31, 61, 62, 93, 122, 124, 151, 155, 181, 183, 186, 211, 217, 241, 244, 248, 271, 279, 302, 305, 310, 331, 341, 362, 366, 372, 403, 421, 422, 427, 434, 453, 465, 482, 488, 496, 527, 541, 542, 543, 549, 558, 571, 589, 601, 604, 610, 620, 631, 633, 651, 661, 662

Offset: 1

Author

Arkadiusz Wesolowski, Aug 25 2013

Keywords

• nonn
• less

Comments

Together with 2, supersequence of A228556.

Conjecture: Numbers m such that abs(Sum_{k=1..m} [k|m]*A008683(k)*(-1)^(k/15)) = 0. - Mats Granvik, Jul 06 2024

Examples

			183 = 3*61 is in the sequence because 30*2 + 1 is prime.
211 is in the sequence because it is prime and 211 = 30*7 + 1.
		

Crossrefs

Supersequence of A132230. Cf. A228556.

Programs

PARI

for(n=31, 662, if(setsearch(Set(factor(n)[, 1]%30), 1)==1, print1(n, ", ")));