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 A063645 #19 Jan 13 2025 07:55:49 %S A063645 173,277,607,929,1129,1181,1237,1493,1549,1597,1613,2011,2063,2137, %T A063645 2423,2677,2753,2767,2797,2819,2851,2917,3449,3533,3607,3617,3727, %U A063645 4013,4073,4177,4201,4253,4493,4523,4583,4691,4919,4951,5119,5237,5273,5393,5407,5557 %N A063645 Primes with two representations: p*q*r - 2 = u*v*w + 2 where p, q, r, u, v and w are primes (not necessarily distinct). %H A063645 Alois P. Heinz, <a href="/A063645/b063645.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from Harry J. Smith) %e A063645 5821 is a term: 5821 = A063641(204) = 5823 - 2 = 3*3*647 - 2, 5821 = A063642(225) = 5819 + 2 = 11*23*23 + 2. %p A063645 q:= p-> isprime(p) and map(numtheory[bigomega], {p-2, p+2})={3}: %p A063645 select(q, [$2..6000])[]; # _Alois P. Heinz_, Apr 01 2024 %t A063645 q[p_] := PrimeQ[p] && Union[PrimeOmega /@ {p-2, p+2}] == {3}; %t A063645 Select[Range[2, 6000], q] (* _Jean-François Alcover_, Jan 13 2025, after _Alois P. Heinz_ *) %o A063645 (PARI) { n=0; for (m=2, 10^9, p=prime(m); if (bigomega(p + 2) == 3 && bigomega(p - 2) == 3, write("b063645.txt", n++, " ", p); if (n==1000, break)) ) } \\ _Harry J. Smith_, Aug 27 2009 %Y A063645 Cf. A063641, A063642, A063643, A014612. %K A063645 nonn %O A063645 1,1 %A A063645 _Reinhard Zumkeller_, Jul 21 2001