|
Search: id:A101840
|
|
|
| A101840 |
|
Indices of primes in sequence defined by A(0) = 37, A(n) = 10*A(n-1) - 3 for n > 0. |
|
+0
1
|
|
| 0, 1, 11, 14, 50, 193, 497, 2135, 2821, 3761, 7427
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
COMMENT
|
Numbers n such that (330*10^n + 3)/9 is prime.
Numbers n such that digit 3 followed by n >= 0 occurrences of digit 6 followed by digit 7 is prime.
Numbers corresponding to terms <= 497 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
|
367 is prime, hence 1 is a term.
|
|
PROGRAM
|
(PARI) a=37; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-3)
(PARI) for(n=0, 1500, if(isprime((330*10^n+3)/9), print1(n, ", ")))
|
|
CROSSREFS
|
Cf. A000533, A002275.
a(n) = A102975(n) - 1.
Adjacent sequences: A101837 A101838 A101839 this_sequence A101841 A101842 A101843
Sequence in context: A045139 A043105 A043885 this_sequence A061087 A063964 A139065
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 20 2004
|
|
EXTENSIONS
|
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
|
|
|
Search completed in 0.002 seconds
|
