|
Search: id:A101018
|
|
|
| A101018 |
|
Indices of primes in sequence defined by A(0) = 97, A(n) = 10*A(n-1) + 17 for n > 0. |
|
+0
1
|
|
| 0, 2, 3, 5, 8, 11, 15, 33, 128, 242, 251, 528, 4884, 6362
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
Numbers n such that (890*10^n - 17)/9 is prime.
Numbers n such that digit 9 followed by n >= 0 occurrences of digit 8 followed by digit 7 is prime.
Numbers corresponding to terms <= 528 are certified primes.
|
|
REFERENCES
|
Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
|
|
LINKS
|
Makoto Kamada, Factorizations of near-repdigit numbers.
|
|
EXAMPLE
|
9888887 is prime, hence 5 is a term.
|
|
PROGRAM
|
(PARI) a=97; for(n=0, 1000, if(isprime(a), print1(n, ", ")); a=10*a+17)
(PARI) for(n=0, 1000, if(isprime((890*10^n-17)/9), print1(n, ", ")))
|
|
CROSSREFS
|
Cf. A000533, A002275.
a(n) = A103109(n) - 1.
Sequence in context: A125811 A071424 A008762 this_sequence A006336 A070228 A006304
Adjacent sequences: A101015 A101016 A101017 this_sequence A101019 A101020 A101021
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Nov 27 2004
|
|
EXTENSIONS
|
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
|
|
|
Search completed in 0.002 seconds
|
