A031505 Upper prime of a difference of 4 between consecutive primes.

11, 17, 23, 41, 47, 71, 83, 101, 107, 113, 131, 167, 197, 227, 233, 281, 311, 317, 353, 383, 401, 443, 461, 467, 491, 503, 617, 647, 677, 743, 761, 773, 827, 857, 863, 881, 887, 911, 941, 971, 1013, 1091, 1097, 1217, 1283, 1301, 1307, 1427, 1433, 1451

Offset: 1

Author

Jeff Burch

Keywords

• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Essentially the same as A046132.

Programs

Maple

for i from 1 to 232 do if ithprime(i+1) = ithprime(i) + 4 then print({ithprime(i+1)}); fi; od; # Zerinvary Lajos, Mar 19 2007

Mathematica

Select[Partition[Prime[Range[250]],2,1],#[[2]]-#[[1]]==4&][[All,2]] (* Harvey P. Dale, Feb 02 2023 *)

Formula

a(n) = A029710(n-1) + 4 = A029708(n) + 2.

Extensions

Corrected and extended by Henry Bottomley, Jul 18 2000

Definition clarified by Harvey P. Dale, Feb 02 2023