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A335594 a(n) is the first prime to start a sequence of exactly n primes under the iteration p -> p + (p^2-1)/12. 0
2, 7, 5, 59, 1657459 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No further terms up to 10^8.

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

a(3) = 5 because 5 starts a sequence of exactly 3 primes: 5 -> 5+(5^2-1)/12 = 7 -> 7+(7^2-1)/12 = 11, while 11 + (11^2-1)/12 = 21 is not prime, and 5 is the first prime to do so.

MAPLE

g:= p -> p + (p^2-1)/12:

f:= proc(p)

    if not isprime(p) then 0

    else 1 + procname(g(p))

    fi

end proc:

A:= Vector(5): A[1]:= 2: count:= 1:

p:= 3:

while count < 5 do

p:= nextprime(p);

v:= f(p);

if A[v] = 0 then count:= count+1; A[v]:= p; fi

od:

convert(A, list);

CROSSREFS

Sequence in context: A152555 A343780 A094360 * A051757 A193746 A070524

Adjacent sequences:  A335591 A335592 A335593 * A335595 A335596 A335597

KEYWORD

nonn,more

AUTHOR

J. M. Bergot and Robert Israel, Dec 24 2020

STATUS

approved

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Last modified October 18 14:14 EDT 2021. Contains 348068 sequences. (Running on oeis4.)