

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
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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



