# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a340062 Showing 1-1 of 1 %I A340062 #10 Jan 09 2021 02:12:08 %S A340062 39372,104963700,116479500,182003250,202991022,231362100 %N A340062 Averages k of twin primes such that the sum (with multiplicity) of prime factors of k-1, k and k+1 is a prime power (but not a prime). %e A340062 a(3) = 116479500 is a member because 116579499 and 11657501 are primes and the sum of prime factors of 116579499, 116579500 = 2^2*3*5^3*19*61*67 and 116579501 is 232959169 = 15263^2 where 15263 is prime. %p A340062 filter:= proc(t) %p A340062 local r,s,f; %p A340062 if not(isprime(t-1) and isprime(t+1)) then return false fi; %p A340062 r:= 2*t+add(s[1]*s[2],s=ifactors(t)[2]); %p A340062 f:=numtheory:-factorset(r); %p A340062 nops(f) = 1 and r <> f[1] %p A340062 end proc: %p A340062 select(filter, [seq(t,t=6..3*10^8,6)]); %Y A340062 Cf. A001414, A340060. %K A340062 nonn,more %O A340062 1,1 %A A340062 _J. M. Bergot_ and _Robert Israel_, Dec 27 2020 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE