A220432 - OEIS

%I #23 Jul 10 2024 03:00:40

%S 1,5,11,17,19,23,25,29,31,37,41,43,47,53,55,59,61,67,71,83,85,89,95,

%T 97,101,103,107,109,113,115,121,125,127,131,137,139,145,149,155,157,

%U 167,173,179,181,185,187,191,197,199,205,209,215,223,227,229,233,235

%N Numbers not divisible by 2, 3 or any prime of the form 4x^2+2xy+7y^2 (see A219908).

%C Note that Jagy omitted 19.

%H Reinhard Zumkeller, <a href="/A220432/b220432.txt">Table of n, a(n) for n = 1..10000</a>

%H W. C. Jagy, <a href="https://www.jstor.org/stable/10.4169/amer.math.monthly.119.10.880">Problem 11539</a>, Amer. Math. Monthly, 119 (2012), 884-885.

%o (Haskell)

%o a220432 n = a220432_list !! (n-1)

%o a220432_list = filter (\x -> null $

%o    intersect (a027748_row x) (takeWhile (<= x) a219908_list)) a007310_list

%o -- _Reinhard Zumkeller_, Dec 15 2012

%Y Cf. A219907, A219908.

%Y Cf. A027748, subsequence of A007310.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Dec 15 2012

%E Data fixed and extended by _Reinhard Zumkeller_, Dec 15 2012