Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #27 Sep 09 2022 23:37:58
%S 1,11,19,29,31,41,59,61,71,79,89,101,109,121,131,139,149,151,179,181,
%T 191,199,209,211,229,239,241,251,269,271,281,311,319,331,341,349,359,
%U 361,379,389,401,409,419,421,431,439,449,451,461,479,491,499,509
%N Multiplicative closure of A045468: numbers which are the product of zero or more primes which are 1 or 4 mod 5.
%C The subsequence of A089270 which excludes terms divisible by 5.
%H David Friend, <a href="/A336403/b336403.txt">Table of n, a(n) for n = 1..10000</a>
%H David Friend, <a href="/A336403/a336403_1.pdf">Fibonacci-Like Sequences and their Cassini Constants, Multiplication and Factorisation</a>
%F Numbers of the form r^2 + 3*r*s + s^2 not divisible by 5, where r and s are relatively prime and r > s >= 0.
%Y Cf. A031363 and its subset A089270 and its subset A038872 and its subset A045468.
%K nonn,easy
%O 1,2
%A _David Friend_, Jul 20 2020
%E New name and general cleanup by _Charles R Greathouse IV_, Sep 09 2022