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

1,1

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

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 *)

Crossrefs

Cf. A255609, A285688.

Sequence in context: A087617 A263365 A140157 * A139867 A260674 A090434

Adjacent sequences: A285686 A285687 A285688 * A285690 A285691 A285692

Keyword

nonn

Author

Zak Seidov, Apr 24 2017

Status

approved