|
Search: id:A101956
|
|
|
| A101956 |
|
Indices of primes in sequence defined by A(0) = 29, A(n) = 10*A(n-1) - 51 for n > 0. |
|
+0
1
|
|
| 0, 1, 2, 3, 7, 10, 12, 23, 27, 51, 53, 93, 296, 656, 1005, 5346, 8188, 9313
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
COMMENT
|
Numbers n such that (210*10^n + 51)/9 is prime.
Numbers n such that digit 2 followed by n >= 0 occurrences of digit 3 followed by digit 9 is prime.
Numbers corresponding to terms <= 656 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
|
2339 is prime, hence 2 is a term.
|
|
PROGRAM
|
(PARI) a=29; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-51)
(PARI) for(n=0, 1500, if(isprime((210*10^n+51)/9), print1(n, ", ")))
|
|
CROSSREFS
|
Cf. A000533, A002275.
a(n) = A102951(n) - 1.
Sequence in context: A047531 A102808 A140512 this_sequence A002238 A002255 A088163
Adjacent sequences: A101953 A101954 A101955 this_sequence A101957 A101958 A101959
|
|
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
|
