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A155949 Numbers p with property that p and 5 iterations of f(p) all are primes, where f(p)=p^2+p+41. 0
16355881, 109909799, 156177433, 167667607, 169177649, 196805633, 320142863, 428366489, 610038257, 644062919, 1103804483, 1164167891, 1184418737, 1493813903, 1541169463, 1882406467, 1956211891, 2018075911, 2248153673 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Next term a(20)=2493493447.

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

f(n)=n^2+n+41

n=1, p=16355881:

f(p)=267514859642083 prime,

f(f(p))=71564200129323635349724221013, prime

f(f(f(p))) =5121434740149885026514070854977073540325438908499394967223, prime

f(f(f(f(p)))) prime, f(f(f(f(f(p))))) prime, f(f(f(f(f(f(p)))))) not-prime.

CROSSREFS

Sequence in context: A204604 A253716 A216004 * A192203 A248204 A178555

Adjacent sequences:  A155946 A155947 A155948 * A155950 A155951 A155952

KEYWORD

nonn

AUTHOR

Zak Seidov, Jan 31 2009

STATUS

approved

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Last modified April 18 07:59 EDT 2021. Contains 343084 sequences. (Running on oeis4.)