A117790 Lucas numbers for which the sum of the digits is a prime.

1, 3, 7, 11, 29, 47, 76, 199, 322, 2207, 24476, 1149851, 141422324, 969323029, 2537720636, 10749957122, 73681302247, 119218851371, 312119004989, 505019158607, 2139295485799, 3461452808002, 5600748293801, 100501350283429

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.

Mathematica

Join[{1}, Select[LucasL[Range[100]], PrimeQ[Total[IntegerDigits[#]]]&]] (* Harvey P. Dale, Sep 16 2022 *)

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: A156210 A343718 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