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A101739 Indices of primes in sequence defined by A(0) = 43, A(n) = 10*A(n-1) + 63 for n > 0. 0
0, 2, 3, 7, 13, 15, 23, 60, 79, 86, 103, 107, 143, 2156, 3324, 4121 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers n such that (450*10^n - 63)/9 is prime.

Numbers n such that digit 4 followed by n >= 0 occurrences of digit 9 followed by digit 3 is prime.

Numbers corresponding to terms <= 143 are certified primes.

REFERENCES

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

LINKS

Table of n, a(n) for n=1..16.

Makoto Kamada, Factorizations of near-repdigit numbers.

EXAMPLE

4993 is prime, hence 2 is a term.

PROG

(PARI) a=43; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+63)

(PARI) for(n=0, 1500, if(isprime((450*10^n-63)/9), print1(n, ", ")))

CROSSREFS

Cf. A000533, A002275.

a(n) = A103002(n) - 1.

Sequence in context: A084955 A026472 A225098 * A141633 A045327 A181103

Adjacent sequences:  A101736 A101737 A101738 * A101740 A101741 A101742

KEYWORD

nonn,hard,more

AUTHOR

Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 14 2004

EXTENSIONS

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

STATUS

approved

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Last modified December 19 06:44 EST 2014. Contains 252177 sequences.