|
Search: id:A101970
|
|
|
| A101970 |
|
Indices of primes in sequence defined by A(0) = 23, A(n) = 10*A(n-1) + 53 for n > 0. |
|
+0
1
|
|
| 0, 1, 6, 27, 72, 294, 493, 597, 2599, 3729, 7548
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
COMMENT
|
Numbers n such that (260*10^n - 53)/9 is prime.
Numbers n such that digit 2 followed by n >= 0 occurrences of digit 8 followed by digit 3 is prime.
Numbers corresponding to terms <= 597 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
|
283 is prime, hence 1 is a term.
|
|
PROGRAM
|
(PARI) a=23; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+53)
(PARI) for(n=0, 1500, if(isprime((260*10^n-53)/9), print1(n, ", ")))
|
|
CROSSREFS
|
Cf. A000533, A002275.
a(n) = A102961(n) - 1.
Sequence in context: A012365 A085788 A027276 this_sequence A136105 A027313 A124089
Adjacent sequences: A101967 A101968 A101969 this_sequence A101971 A101972 A101973
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 23 2004
|
|
EXTENSIONS
|
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
|
|
|
Search completed in 0.002 seconds
|
