A122564 - OEIS

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A122564

Twin primes of form 4k-1, 4k+1.

3, 5, 11, 13, 59, 61, 71, 73, 107, 109, 179, 181, 191, 193, 227, 229, 239, 241, 311, 313, 347, 349, 419, 421, 431, 433, 599, 601, 659, 661, 827, 829, 1019, 1021, 1031, 1033, 1091, 1093, 1151, 1153, 1319, 1321, 1427, 1429, 1451, 1453, 1487, 1489, 1607, 1609

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

EXAMPLE

a(3)=11=4*3-1, a(4)=13=4*3+1

MAPLE

i:=1:for k from 1 to 600 do if isprime(4*k-1) and isprime(4*k+1) then a[i]:=4*k-1:a[i+1]:=4*k+1: i:=i+2 fi od: seq(a[n], n=1..i-1);

MATHEMATICA

Select[Partition[Prime[Range[300]], 2, 1], #[[2]]-#[[1]]==2&&Divisible[ Mean[ #], 4]&]//Flatten (* Harvey P. Dale, May 17 2021 *)

CROSSREFS