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A094898 This sequence needs a proper name. 0
7, 0, 0, 17, 0, 0, 0, 0, 0, 41, 0, 0, 0, 0, 0, 0, 71, 0, 0, 83, 0, 0, 0, 0, 101, 0, 0, 113, 0, 0, 0, 131, 0, 0, 0, 0, 0, 0, 0, 0, 167, 0, 0, 0, 0, 0, 0, 0, 197, 0, 0, 0, 0, 0, 0, 227, 0, 233, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 281, 0, 0, 0, 0, 0, 0, 311, 0, 317, 0, 0, 0, 0, 0, 0, 0, 0, 353, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..92.

MATHEMATICA

a=Table[If[PrimeQ[4*n+1]==True&&PrimeQ[4*n+3]==False, 1, 0], {n, 0, 200}]

b=Table[If[PrimeQ[4*n+1]==False&&PrimeQ[4*n+3]==True, 1, 0], {n, 0, 200}]

d=Table[If[PrimeQ[a[[n]]*(4*n+1)+b[[n]]*(4*n+3)]==True, a[[n]]*(4*n+1)+b[[n]]*(4*n+3), 0], {n, 1, 200}]

PROG

(PARI) av(terms) = my(v=[]); for(n=0, oo, if(ispseudoprime(4*n+1) && !ispseudoprime(4*n+3), v=concat(v, [1]), v=concat(v, [0])); if(#v==terms, break)); v

bv(terms) = my(v=[]); for(n=0, oo, if(!ispseudoprime(4*n+1) && ispseudoprime(4*n+3), v=concat(v, [1]), v=concat(v, [0])); if(#v==terms, break)); v

a(n) = my(avv=av(n), bvv=bv(n), x=avv[#avv], y=bvv[#bvv], val=x*(4*n+1)+y*(4*n+3)); if(ispseudoprime(val), return(val), return(0)) \\ Felix Fröhlich, Jul 03 2021; Program adapted from Mathematica code

CROSSREFS

Cf. A094896, A094897.

Sequence in context: A235363 A356592 A211904 * A341806 A340906 A136115

Adjacent sequences:  A094895 A094896 A094897 * A094899 A094900 A094901

KEYWORD

nonn,uned,obsc,less

AUTHOR

Roger L. Bagula, Jun 14 2004

STATUS

approved

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Last modified October 1 07:15 EDT 2022. Contains 357135 sequences. (Running on oeis4.)