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A101526 Indices of primes in sequence defined by A(0) = 67, A(n) = 10*A(n-1) - 33 for n > 0. +0
1
0, 2, 3, 4, 5, 9, 12, 57, 95, 177, 359, 419, 454, 1007, 1516, 2974, 3998, 5424 (list; graph; listen)
OFFSET

1,2

COMMENT

Numbers n such that (570*10^n + 33)/9 is prime.

Numbers n such that digit 6 followed by n >= 0 occurrences of digit 3 followed by digit 7 is prime.

Numbers corresponding to terms <= 454 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

633337 is prime, hence 4 is a term.

PROGRAM

(PARI) a=67; for(n=0, 1200, if(isprime(a), print1(n, ", ")); a=10*a-33)

(PARI) for(n=0, 1200, if(isprime((570*10^n+33)/9), print1(n, ", ")))

CROSSREFS

Cf. A000533, A002275.

a(n) = A103033(n) - 1.

Sequence in context: A038201 A033084 A076134 this_sequence A140298 A107365 A026484

Adjacent sequences: A101523 A101524 A101525 this_sequence A101527 A101528 A101529

KEYWORD

nonn,hard,more

AUTHOR

Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 06 2004

EXTENSIONS

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

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Last modified November 30 22:12 EST 2008. Contains 150989 sequences.


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