A101577 Indices of primes in sequence defined by A(0) = 59, A(n) = 10*A(n-1) - 51 for n > 0.

0, 46, 68, 98, 574, 714, 2178, 10540

Offset

1,2

Comments

Numbers n such that (480*10^n + 51)/9 is prime.

Numbers n such that digit 5 followed by n >= 0 occurrences of digit 3 followed by digit 1 is prime.

Numbers corresponding to terms <= 714 are certified primes.

a(9) > 10^5. - Robert Price, Sep 08 2015

References

Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.

Links

Table of n, a(n) for n=1..8.

Makoto Kamada, Prime numbers of the form 533...339.

Index entries for primes involving repunits.

Formula

a(n) = A103012(n+1) - 1.

Example

59 is prime, hence 0 is a term.

Mathematica

Select[Range[0, 10000], PrimeQ[(480*10^# + 51)/9] &] (* Robert Price, Sep 08 2015 *)

Prog

(PARI) a=59; for(n=0, 1000, if(isprime(a), print1(n, ", ")); a=10*a-51)
(PARI) for(n=0, 1000, if(isprime((480*10^n+51)/9), print1(n, ", ")))

Crossrefs

Cf. A000533, A002275, A103012.

Sequence in context: A118698 A350203 A103381 * A051413 A167283 A085434

Adjacent sequences: A101574 A101575 A101576 * A101578 A101579 A101580

Keyword

nonn,more

Author

Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 09 2004

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008

a(8) from Kamada data by Ray Chandler, Apr 30 2015

Status

approved