The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A004090

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A004090

Sum of digits of Fibonacci numbers.
(history; published version)

#40 by Alois P. Heinz at Tue Oct 24 19:43:06 EDT 2023

STATUS

proposed

approved

#39 by Jon E. Schoenfield at Tue Oct 24 19:30:28 EDT 2023

STATUS

editing

proposed

#38 by Jon E. Schoenfield at Tue Oct 24 19:30:16 EDT 2023

COMMENTS

a(n) and FibFibonacci(n) are congruent modulo 9 which implies that (a(n) mod 9) is equal to (FibFibonacci(n) mod 9) A007887(n). Thus (a(n) mod 9) is periodic with the Pisano period A001175(9) = 24. - Hieronymus Fischer, Jun 25 2007

It appears that a(n) - n stays negative for n > 5832, which explains why A020995 is finite. - T. D. Noe, Mar 19 2012

FORMULA

a(n) = FibFibonacci(n) - 9*sumSum_{k>0, } floor(FibFibonacci(n)/10^k)}. - Hieronymus Fischer, Jun 25 2007

STATUS

approved

editing

#37 by Charles R Greathouse IV at Thu Sep 08 08:44:32 EDT 2022

PROG

(MAGMAMagma) [&+Intseq(Fibonacci(n)): n in [0..80] ]; // Vincenzo Librandi, Jun 18 2015

Discussion

Thu Sep 08

08:44

OEIS Server: https://oeis.org/edit/global/2944

#36 by Charles R Greathouse IV at Mon Jun 19 03:19:56 EDT 2017

STATUS

editing

approved

#35 by Charles R Greathouse IV at Mon Jun 19 03:19:37 EDT 2017

CROSSREFS

Cf. A000045, A030132, A007953, A246558, A261587, A068500.

Cf. A007953, A246558.

Cf. A261587.

Cf. A068500.

STATUS

approved

editing

#34 by Reinhard Zumkeller at Mon Oct 26 12:21:58 EDT 2015

STATUS

editing

approved

#33 by Reinhard Zumkeller at Mon Oct 26 12:21:51 EDT 2015

CROSSREFS

Cf. A068500.

STATUS

approved

editing

#32 by Reinhard Zumkeller at Wed Sep 09 16:49:40 EDT 2015

STATUS

editing

approved

#31 by Reinhard Zumkeller at Wed Sep 09 16:37:13 EDT 2015

CROSSREFS

Cf. A261587.

STATUS

approved

editing