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 A159687 Number of strong primes < 10^n. 0
 0, 10, 73, 574, 4543, 37723, 320991, 2796946, 24758534, 222126290, 201400162 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The number of strong primes < n ~ sum of strong primes < sqrt(n). The number of strong primes < 10^11 = 2014200162 and the sum of strong primes < 10^5.5 = 1972716560, for an error of 0.0206. LINKS Cino Hilliard, Sum of Strong Primes FORMULA Given 3 consecutive primes p1,p2,p3, p2 is a strong prime if p2 > (p1+p2)/2. Or, primes that are greater than the arithmetic mean of their immediate surrounding primes. EXAMPLE The strong primes < 10^2 are 11, 17, 29, 37, 41, 59, 67, 71, 79, 97. These add up to 10 which is the second term in the sequence. PROG (Other) See the link for Gcc programs that count and sum these primes. CROSSREFS Sequence in context: A200580 A181678 A206817 * A199556 A044197 A044578 Adjacent sequences:  A159684 A159685 A159686 * A159688 A159689 A159690 KEYWORD nonn AUTHOR Cino Hilliard, Apr 19 2009 EXTENSIONS Edited by N. J. A. Sloane, Apr 20 2009 STATUS approved

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Last modified September 21 14:54 EDT 2020. Contains 337272 sequences. (Running on oeis4.)