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 A076106 Out of all the n-digit primes, which one takes the longest time to appear in the digits of Pi (ignoring the initial 3)? The answer is a(n), and it appears at position A076130(n). 3
 7, 73, 373, 9337, 35569, 805289, 9271903 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(8) requires > 1 billion digits of Pi. - Michael S. Branicky, Jul 08 2021 LINKS Carlos Rivera, Puzzle 40. The Pi Prime Search Puzzle (by Patrick De Geest), The Prime Puzzles and Problems Connection. EXAMPLE Of all the 2-digit primes, 11 to 97, the last one to appear in Pi is 73, at position 299 (see A076130). - N. J. A. Sloane, Nov 28 2019 PROG (Python) # download https://stuff.mit.edu/afs/sipb/contrib/pi/pi-billion.txt, then with open('pi-billion.txt', 'r') as f: digits_of_pi = f.readline()[2:] # from sympy import S # digits_of_pi = str(S.Pi.n(72*10**4))[2:] # alternate to loading data from sympy import primerange def A076106_A076130(n):     global digits_of_pi     bigp, bigloc = None, -1     for p in primerange(10**(n-1), 10**n):         loc = digits_of_pi.find(str(p))         if loc == -1: print("not enough digits", n, p)         if loc > bigloc:             bigloc = loc             bigp = p     return (bigp, bigloc+1) print([A076106_A076130(n)[0] for n in range(1, 6)]) # Michael S. Branicky, Jul 08 2021 CROSSREFS Cf. A000796, A047658, A076094, A076129, A076130. Sequence in context: A139966 A175205 A027017 * A202042 A294291 A318688 Adjacent sequences:  A076103 A076104 A076105 * A076107 A076108 A076109 KEYWORD hard,more,nonn,base AUTHOR Jean-Christophe Colin (jc-colin(AT)wanadoo.fr), Oct 31 2002 EXTENSIONS Definition clarified by N. J. A. Sloane, Nov 28 2019 a(7) from Michael S. Branicky, Jul 08 2021 STATUS approved

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Last modified December 8 22:49 EST 2021. Contains 349596 sequences. (Running on oeis4.)