|
|
A101517
|
|
Indices of primes in sequence defined by A(0) = 61, A(n) = 10*A(n-1) - 9 for n > 0.
|
|
1
|
|
|
0, 1, 7, 8, 14, 19, 25, 37, 44, 64, 111, 243, 302, 392, 559, 838, 1008, 1018, 1172, 1333, 2235, 2628, 4425, 8847, 20811, 37743, 72925, 86286
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
COMMENTS
|
Numbers n such that 60*10^n + 1 is prime.
Numbers n such that digit 6 followed by n >= 0 occurrences of digit 0 followed by digit 1 is prime.
Numbers corresponding to terms <= 838 are certified primes.
Certified primality of numbers corresponding to terms 1008,1018,1172,1333 with Primo. - Ryan Propper, Jun 20 2005
|
|
REFERENCES
|
Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
600000001 is prime, hence 7 is a term.
|
|
PROG
|
(PARI) a=61; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-9)
(PARI) for(n=0, 1500, if(isprime(60*10^n+1), print1(n, ", ")))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 06 2004
|
|
EXTENSIONS
|
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
|
|
STATUS
|
approved
|
|
|
|