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A031938
Lower prime of a difference of 20 between consecutive primes.
15
887, 1637, 3089, 3413, 3947, 5717, 5903, 5987, 6803, 7649, 8243, 8543, 8783, 8867, 9257, 10223, 10433, 10667, 11027, 11093, 11177, 11447, 11597, 11657, 11867, 11987, 13127, 13421, 13649, 14087, 14177, 15473, 16943, 17519, 17807
OFFSET
1,1
FORMULA
a(n) = prime(A320708(n)). - R. J. Mathar, Apr 30 2024
EXAMPLE
887 is a term as the next prime is 907.
MATHEMATICA
(*M6*) a=887; S={}; Do[b=NextPrime[a]; If[b-a==20, AppendTo[S, a]]; a=b, {10^4}]; S [Zak Seidov, Aug 14 2009]
Transpose[Select[Partition[Prime[Range[2000]], 2, 1], Last[#] - First[#] == 20 &]][[1]] (* Bruno Berselli, Apr 09 2013 *)
PROG
(Magma) [p: p in PrimesUpTo(20000) | NextPrime(p)-p eq 20]; // Bruno Berselli, Apr 09 2013
CROSSREFS
Sequence in context: A103811 A190354 A164513 * A165504 A351667 A136966
KEYWORD
nonn
AUTHOR
EXTENSIONS
Entries and b-file checked by Zak Seidov, Aug 14 2009
STATUS
approved