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A202997 a(1) = 3 ; a(n+1) is the prime number obtained by the concatenation {p, a(n)} where p is the smallest prime prefix. 0
3, 23, 223, 31223, 231223, 31231223, 2931231223, 372931231223, 17372931231223, 1317372931231223, 1971317372931231223, 1571971317372931231223, 891571971317372931231223, 79891571971317372931231223, 25179891571971317372931231223, 4325179891571971317372931231223 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

By Xylouris' version of Linnik's theorem, a(n) << 3^(6.2^n + cn) for some constant c. [Charles R Greathouse IV, Dec 27 2011]

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

a(1) = 3;

a(2) = 23 because 2 is the smallest prime prefix and 23 is prime;

a(3) = 223 because 2 is the smallest prime prefix and 223 is prime;

a(4) = 31223 because 31 is the smallest prime prefix and 31223 is prime.

MAPLE

a0:=3: printf(`%d, `, a0):for it from 1 to 20 do: i:=0:for n from 1 to 1000 while(i=0)  do:p0:=ithprime(n):n0:=length(a0):x:=p0*10^n0+a0: if type(x, prime)=true then printf(`%d, `, x):i:=1:a0:=x:else fi:od:od:

CROSSREFS

Cf. A173291.

Sequence in context: A068691 A093135 A305754 * A093162 A328808 A206763

Adjacent sequences:  A202994 A202995 A202996 * A202998 A202999 A203000

KEYWORD

nonn,base

AUTHOR

Michel Lagneau, Dec 27 2011

STATUS

approved

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Last modified August 3 05:52 EDT 2020. Contains 336197 sequences. (Running on oeis4.)