A282424 Semiprimes p such that next semiprime after p is p + 50.

1226777, 4732631, 5093729, 9210671, 12515461, 12917989, 16121409, 16183253, 16698881, 17263069, 19418903, 23003807, 24534161, 26519563, 26726659, 27625067, 29605299, 29772471, 32655031, 34027277, 34366179, 35340719, 37570683, 38117319, 38687461, 39038399, 39479381

Offset: 1

Author

Zak Seidov, Feb 14 2017

Keywords

• nonn

Comments

All terms are odd because even semiprime 2*p plus 50 = 2*(p+25) is multiple of 4 and not semiprime.

Note that a(1) = 1226777 = A131109(50).

Smallest possible difference is 50 but among first 10000 terms

the least difference 100 is between a(325) = 228601303 and a(326) = 228601403.

Links

• Zak Seidov, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001358, A131109, A217030, A217335, A217357, A282407.

Programs

PARI

lista(nn) = my(r); for(k=1, nn, if(bigomega(k)==2, if(k-r==50, print1(r, ", ")); r=k)); \\ Jinyuan Wang, May 23 2021