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A112879 Define a(0)=3; then a(n)=k*a(n-1)^2-1=least prime first of twin primes. 1
3, 107, 206081, 20894934252011 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

k sequence in A112880

LINKS

Table of n, a(n) for n=0..3.

EXAMPLE

12*3^2-1=107, 107 and 109 twin primes so a(1)=107

18*107^2-1=206081, 206081 and 206083 twin primes so a(2)=206081

a(3)=492*(18*(12*3^2-1)^2-1)^2-1

a(4)=702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1

a(5)=2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1

a(6)=2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1

a(7)=130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1

a(8)=980910*(130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1

a(9)=5528418*(980910*(130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1

a(10)=21357012*(5528418*(980910*(130650*(2370*(2310*(702*(492*(18*(12*3^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1)^2-1

CROSSREFS

Cf. A112880.

Sequence in context: A261997 A061308 A302060 * A172271 A053861 A041635

Adjacent sequences:  A112876 A112877 A112878 * A112880 A112881 A112882

KEYWORD

hard,nonn

AUTHOR

Pierre CAMI, Oct 01 2005

STATUS

approved

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Last modified October 15 05:43 EDT 2019. Contains 328026 sequences. (Running on oeis4.)