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A101067 Indices of primes in sequence defined by A(0) = 83, A(n) = 10*A(n-1) + 13 for n > 0. 0
0, 2, 3, 9, 14, 24, 68, 158, 165, 260, 441, 1338, 1796, 2169, 3162, 3471, 4916 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Numbers n such that (760*10^n - 13)/9 is a prime.

Numbers n such that digit 8 followed by n >= 0 occurrences of digit 4 followed by digit 3 is prime.

Numbers corresponding to terms <= 441 are certified primes.

REFERENCES

Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.

FORMULA

a(n) = A103080(n) - 1. - Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008

EXAMPLE

84443 is prime, hence 3 is a term.

PROG

(PARI) a=83; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+13)

(PARI) for(n=0, 1500, if(isprime((760*10^n-13)/9), print1(n, ", ")))

CROSSREFS

Cf. A000533, A002275.

Sequence in context: A116222 A048038 A113501 * A056645 A047171 A094557

Adjacent sequences:  A101064 A101065 A101066 * A101068 A101069 A101070

KEYWORD

nonn,hard,more

AUTHOR

Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Nov 30 2004

EXTENSIONS

5 more terms from Ryan Propper (rpropper(AT)stanford.edu), Jun 18 2005

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.