A285689 a(1) = 2; a(n + 1) = smallest prime > a(n) such that a(n + 1) - a(n) is the product of four primes.

2, 83, 107, 131, 167, 191, 227, 251, 307, 331, 347, 383, 419, 443, 467, 491, 547, 563, 587, 641, 677, 701, 757, 773, 797, 821, 857, 881, 937, 953, 977, 1013, 1049, 1103, 1163, 1187, 1223, 1259, 1283, 1307, 1361, 1451, 1487, 1511, 1567, 1583, 1607, 1663, 1699, 1723, 1747, 1783, 1823

Offset: 1

Author

Zak Seidov, Apr 24 2017

Keywords

• nonn

Comments

First differences: 81, 24, 24, 36, 24, 36, 24, 56, 24, 16, 36, 36, 24, 24, 24, 56, 16, 24, 54, 36, 24,...

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A255609, A285688.

Programs

Maple

A[1]:= 2: p:= 2: n:= 1:
while n < 60 do
    p:= nextprime(p);
    if numtheory:-bigomega(p-A[n]) = 4 then n:= n+1; A[n]:= p; fi
od:
seq(A[i],i=1..60); # Robert Israel, Nov 28 2019

Mathematica

NestList[Module[{p = NextPrime@ #}, While[PrimeOmega[p - #] != 4, p = NextPrime@ p]; p] &, 2, 52] (* Michael De Vlieger, Apr 25 2017 *)