This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A326581 #9 Jul 08 2025 06:02:59 %S A326581 1,3,5,7,9,11,13,17,19,23,25,29,31,37,41,43,47,49,53,59,61,67,71,73, %T A326581 79,81,83,89,97,101,103,107,109,113,121,127,131,137,139,149,151,157, %U A326581 163,167,169,173,179,181,191,193,197,199,211,223,225,227,229,233,239,241 %N A326581 Odd integers which are prime or square. %C A326581 Contains for example 729=27^2 and hence differs from A062090. - _R. J. Mathar_, Jul 08 2025 %F A326581 Union of A065091 and A016754. %p A326581 s := n -> if irem(n, 2) = 1 and (isprime(n) or issqr(n)) then n else NULL fi: %p A326581 seq(s(n), n=0..241); %t A326581 Select[Range[1, 241, 2], Or[IntegerQ@ Sqrt@ #, PrimeQ@ #] &] (* _Michael De Vlieger_, Jul 15 2019 *) %Y A326581 Cf. A065091, A000040, A016754, A000290, A326583. %K A326581 nonn %O A326581 1,2 %A A326581 _Peter Luschny_, Jul 15 2019