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A122567
Twin primes modulo 4.
0
3, 1, 3, 3, 1, 1, 3, 1, 3, 1, 3, 3, 1, 3, 1, 1, 3, 3, 1, 1, 3, 1, 3, 3, 1, 3, 1, 1, 3, 3, 1, 3, 1, 1, 3, 1, 3, 3, 1, 3, 1, 3, 1, 3, 1, 1, 3, 1, 3, 1, 3, 3, 1, 1, 3, 1, 3, 3, 1, 1, 3, 1, 3, 3, 1, 1, 3, 1, 3, 3, 1, 3, 1, 1, 3, 1, 3, 3, 1, 3, 1, 1, 3, 1, 3, 1, 3, 1, 3, 3, 1, 3, 1, 3, 1, 1, 3, 3, 1, 3, 1, 3, 1, 3, 1
OFFSET
1,1
EXAMPLE
The twin primes are 3,5,7,11,13,17,19,... and mod 4 is 3,1,3,3,1,1,3...
MAPLE
a[1]:=3:i:=2:for k from 5 to 3000 do if isprime(k) and isprime(k+2) then a[i]:=k mod 4:a[i+1]:=k+2 mod 4: i:=i+2 fi od: seq(a[n], n=1..i-1);
CROSSREFS
Cf. A001097.
Sequence in context: A298262 A359525 A124814 * A122431 A279340 A089607
KEYWORD
nonn
AUTHOR
Miklos Kristof, Sep 21 2006
STATUS
approved