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A228541 Numbers having at least one prime factor of the form 30*k + 1. 2

%I #19 Jul 06 2024 14:02:18

%S 31,61,62,93,122,124,151,155,181,183,186,211,217,241,244,248,271,279,

%T 302,305,310,331,341,362,366,372,403,421,422,427,434,453,465,482,488,

%U 496,527,541,542,543,549,558,571,589,601,604,610,620,631,633,651,661,662

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

%C Together with 2, supersequence of A228556.

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

%e 183 = 3*61 is in the sequence because 30*2 + 1 is prime.

%e 211 is in the sequence because it is prime and 211 = 30*7 + 1.

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

%Y Supersequence of A132230. Cf. A228556.

%K nonn,less

%O 1,1

%A _Arkadiusz Wesolowski_, Aug 25 2013

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Last modified August 29 12:14 EDT 2024. Contains 375516 sequences. (Running on oeis4.)