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A078653
a(n) = prime(k) where k = n-th prime congruent to 1 mod 4.
2
11, 41, 59, 109, 157, 179, 241, 283, 367, 461, 509, 547, 599, 617, 773, 859, 919, 1031, 1087, 1171, 1201, 1447, 1471, 1523, 1621, 1723, 1787, 1823, 1913, 2081, 2099, 2269, 2351, 2381, 2549, 2683, 2719
OFFSET
1,1
COMMENTS
Sum 1/a(n) appears to converge albeit slowly.
LINKS
FORMULA
a(n) = A000040(A002144(n)). [Bruno Berselli, Aug 14 2012]
MATHEMATICA
With[{pc14=Select[Prime[Range[100]], Mod[#, 4]==1&]}, Flatten[Table[ Prime[ Take[ pc14, {n}]], {n, 40}]]] (* Harvey P. Dale, Aug 12 2011 *)
PROG
(PARI) pip(n, m, r) = {sr=0; forprime(x=3, n, if(x%m == r, v=prime(x); sr+=1.0/v; print1(v" "); ) ); print(); print("m="m" r="r" sr="sr); }
(Magma) [NthPrime(n): n in PrimesUpTo(400) | n mod 4 eq 1]; // Bruno Berselli, Aug 14 2012
CROSSREFS
Sequence in context: A370156 A122015 A192820 * A040167 A040170 A333085
KEYWORD
nonn,easy
AUTHOR
Cino Hilliard, Dec 14 2002
EXTENSIONS
Offset changed from 0 to 1 by Vincenzo Librandi, Aug 14 2012
STATUS
approved