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 A117790 Lucas numbers for which the sum of the digits is a prime. 1
 1, 3, 7, 11, 29, 47, 76, 199, 322, 2207, 24476, 1149851, 141422324, 969323029, 2537720636, 10749957122, 73681302247, 119218851371, 312119004989, 505019158607, 2139295485799, 3461452808002, 5600748293801, 100501350283429 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..720 EXAMPLE 199 is in the sequence because (1) it is a Lucas number and (2) the sum of its digits 1+9+9=19 is a prime number. PROG (Python) from sympy import isprime A117790_list, a, b = [1], 1, 3 for _ in range(10**6):     if isprime(sum(int(d) for d in str(b))):         A117790_list.append(b)     a, b = b, a+b # Chai Wah Wu, Dec 25 2015 CROSSREFS Cf. A000204. Sequence in context: A194373 A156210 A264803 * A014447 A233517 A125879 Adjacent sequences:  A117787 A117788 A117789 * A117791 A117792 A117793 KEYWORD base,nonn AUTHOR Luc Stevens (lms022(AT)yahoo.com), Apr 15 2006 EXTENSIONS a(6) corrected by Klaus Brockhaus, Apr 17 2006 STATUS approved

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Last modified June 1 02:09 EDT 2020. Contains 334758 sequences. (Running on oeis4.)