|
Search: id:A101129
|
|
|
| A101129 |
|
Indices of primes in sequence defined by A(0) = 73, A(n) = 10*A(n-1) - 27 for n > 0. |
|
+0
1
|
|
| 0, 3, 5, 15, 21, 38, 102, 162, 239, 1047, 1973, 2558, 5879
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
Numbers n such that 70*10^n + 3 is prime.
Numbers n such that digit 7 followed by n >= 0 occurrences of digit 0 followed by digit 3 is prime.
Numbers corresponding to terms <= 239 are certified primes.
Certified primality of number corresponding to term 1047 with Primo. - Ryan Propper (rpropper(AT)stanford.edu), Jun 20 2005
|
|
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
|
7000003 is prime, hence 5 is a term.
|
|
PROGRAM
|
(PARI) a=73; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-27)
(PARI) for(n=0, 1500, if(isprime(70*10^n+3), print1(n, ", ")))
|
|
CROSSREFS
|
Cf. A000533, A002275.
a(n) = A097970(n) - 1.
Sequence in context: A070079 A142717 A057742 this_sequence A128396 A155173 A121219
Adjacent sequences: A101126 A101127 A101128 this_sequence A101130 A101131 A101132
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 03 2004
|
|
EXTENSIONS
|
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
|
|
|
Search completed in 0.002 seconds
|
