A045881 Smallest of first string of exactly 2n-1 consecutive composite integers.

4, 8, 24, 90, 140, 200, 114, 1832, 524, 888, 1130, 1670, 2478, 2972, 4298, 5592, 1328, 9552, 30594, 19334, 16142, 15684, 81464, 28230, 31908, 19610, 35618, 82074, 44294, 43332, 34062, 89690, 162144, 134514, 173360, 31398, 404598, 212702, 188030, 542604

Offset: 1

Author

Erich Friedman

Keywords

• nonn
• nice

Links

• Donovan Johnson, Table of n, a(n) for n = 1..672 (from Nicely link)
• Thomas R. Nicely, First occurrence prime gaps [For local copy see A000101]

Crossrefs

Equals A000230(n) + 1.

Programs

Mathematica

Reap[For[k=2, k <= 80, k = k+2, p=3; q=5; While[q-p != k, p=q; q=NextPrime[p+1]]; Print[p+1]; Sow[p+1]]][[2, 1]] (* Jean-François Alcover, May 17 2013, after Klaus Brockhaus *)
With[{cmps=Table[If[CompositeQ[n],1,0],{n,10^6}]},Flatten[Table[ SequencePosition[ cmps,Join[{0},PadRight[{},i,1],{0}],1],{i,1,81,2}],1][[All,1]]+1] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 02 2017 *)

PARI

forstep(k=2,80,2,p=3;q=5;while(q-p!=k,p=q;q=nextprime(p+1));print1(p+1,",")) \\ Klaus Brockhaus, Jan 24 2008

Extensions

More terms from Harvey P. Dale, Jul 27 2001