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 A244255 a(n) = the frequency of the most common 2-digit ending of a prime with n digits. 0
 1, 6, 31, 220, 1748, 14746, 127601, 1127869, 10107163, 91579392, 837273621 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 LINKS Table of n, a(n) for n=2..12. EXAMPLE Of the 3-digit primes, the most common two-digit ending occurs 6 times. Thus a(3) = 6. PROG (Python) import sympy from sympy import isprime def end1(d, n): ..lst = [] ..for k in range(10**(d-1), 10**d): ....num = '' ....count = 0 ....for i in range(10**(n-d-1), 10**(n-d)): ......if isprime(int(str(i)+str(k))): ........count += 1 ....lst.append(count) ..return max(lst) n = 3 while n < 10: ..print(end1(2, n), end=', ') ..n += 1 CROSSREFS Cf. A244190. Sequence in context: A121754 A351818 A200775 * A299550 A208594 A318539 Adjacent sequences: A244252 A244253 A244254 * A244256 A244257 A244258 KEYWORD nonn,base,hard,more AUTHOR Derek Orr, Jun 24 2014 EXTENSIONS a(8)-a(12) from Hiroaki Yamanouchi, Aug 26 2014 STATUS approved

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Last modified August 11 01:05 EDT 2024. Contains 375059 sequences. (Running on oeis4.)