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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
 0, 2, 3, 4, 5, 9, 12, 57, 95, 177, 359, 419, 454, 1007, 1516, 2974, 3998, 5424 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 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. PROG (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 * A140298 A107365 A026484 Adjacent sequences:  A101523 A101524 A101525 * A101527 A101528 A101529 KEYWORD nonn,hard,more AUTHOR Klaus Brockhaus 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 STATUS approved

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