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%I #18 Sep 10 2024 04:30:58
%S 31,61,151,181,241,271,541,601,751,811,1201,1621,1801,2161,2251,3001,
%T 4051,4801,4861,6481,7681,8101,8641,9001,9601,9721,11251,14401,15361,
%U 19441,21601,21871,22501,23041,24001,32401,33751,36451,37501,43201,54001,57601,58321
%N Primes of the form 2^a * 3^b * 5^c + 1 for positive a, b, c.
%H T. D. Noe, <a href="/A114991/b114991.txt">Table of n, a(n) for n=1..1000</a>
%e a(1) = 31 = 2^1 * 3^1 * 5^1 + 1.
%e a(2) = 61 = 2^2 * 3^1 * 5^1 + 1.
%e a(3) = 151 = 2^1 * 3^1 * 5^2 + 1.
%e a(4) = 181 = 2^2 * 3^2 * 5^1 + 1.
%e Values include 30000001 = 2^7 * 3^1 * 5^7 + 1, 90000000001 = 2^9 * 3^2 * 5^9 + 1.
%Y Cf. A000040, A005109, A030430.
%Y Cf. A143207.
%K easy,nonn
%O 1,1
%A _Jonathan Vos Post_, Feb 22 2006