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A090658
Numbers n such that n-1 is a prime of the form 4k+3.
1
4, 8, 12, 20, 24, 32, 44, 48, 60, 68, 72, 80, 84, 104, 108, 128, 132, 140, 152, 164, 168, 180, 192, 200, 212, 224, 228, 240, 252, 264, 272, 284, 308, 312, 332, 348, 360, 368, 380, 384, 420, 432, 440, 444, 464, 468, 480, 488, 492, 500, 504, 524, 548, 564, 572
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)+A089257(n), A089193(n)+A089257(n)-5.
MATHEMATICA
okQ[n_]:=Module[{x=n-1}, PrimeQ[x]&&IntegerQ[(x-3)/4]]; Select[Range[1, 1000, 1], okQ] (* Vincenzo Librandi, Dec 13 2011 *)
Select[4*Range[0, 200]+3, PrimeQ]+1 (* Harvey P. Dale, Sep 25 2017 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Dec 14 2003
EXTENSIONS
Corrected and extended by T. D. Noe, Oct 25 2006
STATUS
approved