A020997 Numbers n such that the sum of the digits of Lucas(n) is n.

1, 29, 43, 115, 124, 198, 431, 719, 979, 1496

Offset

1,2

Comments

No more terms < 200000. - Manfred Scheucher, Jun 12 2015

No more terms < 5400000. - Dana Jacobsen, Sep 07 2015

Links

Table of n, a(n) for n=1..10.

Manfred Scheucher, Sage Script

David Terr, On the Sums of Digits of Fibonacci Numbers, Fibonacci Quarterly 34, Aug. 1996, pp. 349-355.

Mathematica

Do[ If[ Mod[ 2Fibonacci[n + 1] - Fibonacci[n], 9] == Mod[n, 9], If[ Plus @@ IntegerDigits[ 2Fibonacci[n + 1] - Fibonacci[n]] == n, Print[n]]], {n, 0, 10^5}] (* Robert G. Wilson v *)
Select[Range[0, 10^4], Plus@@IntegerDigits[LucasL[#]]==#&] (* Vincenzo Librandi, Feb 18 2015 *)

Prog

(PARI) isok(n) = sumdigits(fibonacci(n+1)+fibonacci(n-1)) == n; \\ Michel Marcus, Feb 18 2015
(Perl) use ntheory ":all"; for (1..1e5) { say if $_ == sumdigits(lucasv(1, -1, $_)) } # Dana Jacobsen, Sep 06 2015

Crossrefs

Sequence in context: A043951 A042973 A323628 * A108280 A248429 A077782

Adjacent sequences: A020994 A020995 A020996 * A020998 A020999 A021000

Keyword

nonn,base,more

Author

Sven Simon

Status

approved