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 A075284 #11 Apr 27 2024 02:17:54 %S A075284 18,45,99,279,747,909,1611,1737,2007,2259,2439,2799,3879,5193,5571, %T A075284 5787,6147,6219,6471,6813,6849,7677,8271,8577,8703,8739,8793,9279, %U A075284 9549,9621,10107,10161,10629,10953,11241,11511,11619,11709,13329,14031 %N A075284 Interprimes which are of the form s*prime, s=9. %C A075284 Interprimes which are of the form s*prime are in A075277-A075296 (s = 2-21). Case s = 1 is impossible. %H A075284 Harvey P. Dale, <a href="/A075284/b075284.txt">Table of n, a(n) for n = 1..1000</a> %e A075284 279 is an interprime and 279/9 = 31 is prime. %t A075284 s=9; Select[Table[(Prime[n+1]+Prime[n])/2, {n, 2, 1000}], PrimeQ[ #/s]&] %t A075284 Select[Mean/@Partition[Prime[Range[2000]],2,1],PrimeQ[#/9]&] (* _Harvey P. Dale_, Apr 27 2024 *) %Y A075284 Cf. A075277-A075296. %K A075284 easy,nonn %O A075284 1,1 %A A075284 _Zak Seidov_, Sep 12 2002