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

Vincenzo Librandi, Table of n, a(n) for n = 1..5000

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

Cf. A002145, A087915, A089193, A089257.

Sequence in context: A311656 A311657 A033691 * A268799 A269711 A122108

Adjacent sequences:  A090655 A090656 A090657 * A090659 A090660 A090661

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Dec 14 2003

EXTENSIONS

Corrected and extended by T. D. Noe, Oct 25 2006

STATUS

approved

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Last modified July 14 16:21 EDT 2020. Contains 335729 sequences. (Running on oeis4.)