A369464 Numbers for which there is no representation as a sum (p*q + p*r + q*r) with three odd primes p <= q <= r.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 72, 73, 74, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 88

Offset

1,3

Links

Table of n, a(n) for n=1..82.

Prog

(PARI)
isA369251(n) = if(3!=(n%4), 0, my(v = [3, 3], ip = #v, r); while(1, r = (n-(v[1]*v[2])) / (v[1]+v[2]); if(r < v[2], ip--, ip = #v; if(1==denominator(r) && isprime(r), return(1))); if(!ip, return(0)); v[ip] = nextprime(1+v[ip]); for(i=1+ip, #v, v[i]=v[i-1])));
isA369464(n) = !isA369251(n);

Crossrefs

Complement of A369251. Numbers not in A369252.

Union of A004773 and A369056.

Positions of 0's in A369054.

Cf. A098700, A369248, A369249, A369463 (subsequences).

Sequence in context: A154470 A194907 A090106 * A167662 A309810 A246095

Adjacent sequences: A369461 A369462 A369463 * A369465 A369466 A369467

Keyword

nonn

Author

Antti Karttunen, Jan 24 2024

Status

approved