A228541 - OEIS

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

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OFFSET

1,1

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

LINKS

Table of n, a(n) for n=1..53.

EXAMPLE

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.

PROG