A359640 a(n) is the least odd prime not in A001359 such that all subsequent composites in the gap up to the next prime have exactly n odd prime factors, counted with multiplicity.

307, 1999, 101527, 7146697, 272572999, 4809363523

Offset: 2

Author

Hugo Pfoertner, Jan 16 2023

Keywords

• nonn
• hard
• more

Examples

			a(2) = 307: 308 = 2^2*7*11, 309 = 3*103, 310 = 2*5*31, all have exactly 2 odd prime factors.
		

Crossrefs

Cf. A001222, A001359, A087436, A359637, A359639.

Programs

PARI

a087436(n) = bigomega (n >> valuation (n, 2));
a359640(maxp) = {my(k=2, pp=5); forprime (p=7, maxp, my(mi=oo, ma=0); if (p-pp>2, for (j=pp+1, p-1, my(mo=a087436(j)); if (mo