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 A236670 Start with 6; thereafter, primes obtained by concatenating to the end of previous term the next smallest number that will produce a prime. 0
 6, 61, 613, 6131, 613141, 61314119, 6131411917, 61314119171, 6131411917181, 613141191718127, 61314119171812789, 613141191718127893, 61314119171812789379, 6131411917181278937929, 61314119171812789379291, 61314119171812789379291111 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n+1) is the next smallest prime beginning with a(n). Initial term is 6. After a(1), these are the primes arising in A069608. LINKS Table of n, a(n) for n=1..16. EXAMPLE a(1) = 6 by definition. a(2) is the next smallest prime beginning with 6, so a(2) = 61. a(3) is the next smallest prime beginning with 61, so a(3) = 613. PROG (Python) import sympy from sympy import isprime def b(x): ..num = str(x) ..n = 1 ..while n < 10**3: ....new_num = str(x) + str(n) ....if isprime(int(new_num)): ......print(int(new_num)) ......x = new_num ......n = 1 ....else: ......n += 1 b(6) CROSSREFS Cf. A069608, A048553, A110773. Sequence in context: A152281 A053462 A160751 * A142970 A034659 A369509 Adjacent sequences: A236667 A236668 A236669 * A236671 A236672 A236673 KEYWORD nonn,base AUTHOR Derek Orr, Jan 29 2014 STATUS approved

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Last modified July 23 19:18 EDT 2024. Contains 374553 sequences. (Running on oeis4.)