A276756 - OEIS

%I #6 Sep 17 2016 10:01:13

%S 1,21,30,979,1411,1463,1547,1742,1947,2059,2090,2210,2318,2405,2419,

%T 2491,2703,2886,2945,3182,3243,3534,3567,16102,17654,20559,21243,

%U 25543,25705,27145,27307,27805,28045,29323,29370,29631,30485,30846,32574,33366,33465,33654

%N Squarefree terms of A276655.

%C Except for the first term, products of distinct primes p_i such that Sum_{p_i} 0.p_i is an integer.

%H Chai Wah Wu, <a href="/A276756/b276756.txt">Table of n, a(n) for n = 1..10000</a>

%F A005117 INTERSECT A276655.

%o (Python)

%o from fractions import Fraction

%o from sympy import factorint, primefactors

%o A276756_list = [1] + [n for n in range(2,10**6) if max(factorint(n).values()) <= 1 and sum(Fraction(p,10**len(str(p))) for p in primefactors(n)).denominator == 1]

%Y Cf. A005117, A276655.

%K nonn

%O 1,2

%A _Chai Wah Wu_, Sep 17 2016