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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
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
Sequence in context: A338697 A168417 A352170 * A127004 A068168 A215126
KEYWORD
nonn,base
AUTHOR
Abhiram R Devesh, Aug 02 2014
STATUS
approved

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Last modified March 28 14:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)