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A090670
Odd numbers k such that 2*k-3 is a prime of the form 4*j+3.
2
3, 5, 7, 11, 13, 17, 23, 25, 31, 35, 37, 41, 43, 53, 55, 65, 67, 71, 77, 83, 85, 91, 97, 101, 107, 113, 115, 121, 127, 133, 137, 143, 155, 157, 167, 175, 181, 185, 191, 193, 211, 217, 221, 223, 233, 235, 241, 245, 247, 251, 253, 263, 275, 283, 287, 295, 301, 305
OFFSET
1,1
REFERENCES
M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997
LINKS
FORMULA
a(n) = A087915(n)+3.
MATHEMATICA
okQ[n_]:=Module[{x=2n-3}, PrimeQ[x]&&IntegerQ[(x-3)/4]]; Select[Range[1, 315, 2], okQ] (* Harvey P. Dale, Jan 12 2011 *)
CROSSREFS
Cf. A050415 (primes of the form 2^k-3).
Sequence in context: A249876 A096169 A225526 * A074832 A075794 A192864
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Dec 17 2003
EXTENSIONS
Offset changed from 0 to 1 by Vincenzo Librandi, Dec 13 2011
STATUS
approved