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A240167 Lesser of the first cousin prime pair with n digits. 2
3, 13, 103, 1009, 10099, 100189, 1000033, 10000453, 100000123, 1000000093, 10000000597, 100000000069, 1000000000189, 10000000000279, 100000000001173, 1000000000000399, 10000000000001719, 100000000000002733, 1000000000000002493, 10000000000000000087 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sum of reciprocals converges towards 0.421066...

It is only a (plausible) conjecture that this sequence is well-defined. See A152052. - N. J. A. Sloane, Aug 22 2014

LINKS

Abhiram R Devesh, Table of n, a(n) for n = 1..100

FORMULA

For n > 1, a(n) = 10^(n-1) + A227432(n-1), assuming a(n) exists. - Jens Kruse Andersen, Aug 22 2014

PROG

(Python)

import sympy

for i in range(100):

    a=(10**i)

    p=sympy.nextprime(a)

    while not sympy.isprime(p+4):

        p=sympy.nextprime(p)

    print(p)

(PARI)

a(n)=my(p=nextprime(10^(n-1))); while(!isprime(p+4), p=nextprime(p+1)); return(p)

vector(50, n, a(n)) \\ Derek Orr, Aug 04 2014

CROSSREFS

Cf. A023200, A152052, A227432, A240170.

Sequence in context: A323687 A338697 A168417 * A127004 A068168 A215126

Adjacent sequences:  A240164 A240165 A240166 * A240168 A240169 A240170

KEYWORD

nonn,base

AUTHOR

Abhiram R Devesh, Aug 02 2014

STATUS

approved

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Last modified September 26 06:16 EDT 2021. Contains 347664 sequences. (Running on oeis4.)