A117789 Lucas numbers which are divisible by the sum of their digits.

1, 3, 4, 7, 18, 322, 5778, 505019158607, 84722519070079276, 1473646213395791149646646123, 105249261265075663875711417309855979021650214636

Offset

1,2

Comments

a(12) has 83 digits and it is too large to include in the data section. - Amiram Eldar, Feb 08 2021

Links

Amiram Eldar, Table of n, a(n) for n = 1..17

Formula

a(n) = A000204(A337449(n+1)). - Amiram Eldar, Feb 08 2021

Example

322 is in the sequence because it is a Lucas number and it is divisible by the sum of its digits, 3+2+2 = 7.

Mathematica

Select[LinearRecurrence[{1, 1}, {1, 3}, 230], Divisible[#, Plus @@ IntegerDigits[#]] &] (* Amiram Eldar, Feb 08 2021 *)

Prog

(PARI) {m=370; a=1; b=3; print1(a, ", ", b, ", "); for(n=3, m, c=b+a; a=b; b=c; s=0; k=b; while(k>0, d=divrem(k, 10); k=d[1]; s=s+d[2]); if(b%s==0, print1(b, ", ")))} \\ Klaus Brockhaus, Apr 17 2006

Crossrefs

Intersection of A000204 and A005349.

Cf. A337449.

Sequence in context: A307738 A041497 A042227 * A169892 A246805 A241660

Adjacent sequences: A117786 A117787 A117788 * A117790 A117791 A117792

Keyword

base,nonn

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 15 2006

Extensions

a(9) corrected, a(10) and a(11) from Klaus Brockhaus, Apr 17 2006

Status

approved