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A101074 Indices of primes in sequence defined by A(0) = 83, A(n) = 10*A(n-1) + 33 for n > 0. 0
0, 1, 2, 12, 18, 61, 79, 125, 167, 194, 308, 409, 480, 607, 740, 878, 1175, 2687, 6235 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

Numbers n such that (780*10^n - 33)/9 is prime.

Numbers n such that digit 8 followed by n >= 0 occurrences of digit 6 followed by digit 3 is prime.

Numbers corresponding to terms <= 878 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

8663 is prime, hence 2 is a term.

PROG

(PARI) a=83; for(n=0, 1200, if(isprime(a), print1(n, ", ")); a=10*a+33)

(PARI) for(n=0, 1200, if(isprime((780*10^n-33)/9), print1(n, ", ")))

CROSSREFS

Cf. A000533, A002275.

a(n) = A103087(n) - 1.

Sequence in context: A032413 A190044 A066238 * A115109 A048001 A109299

Adjacent sequences:  A101071 A101072 A101073 * A101075 A101076 A101077

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

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008

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Last modified February 16 16:51 EST 2012. Contains 205938 sequences.