A339598 Numbers k such that k | Sum_{i=1..k} A000045(i) and k+1 | Sum_{i=1..k+1} A000045(i).

1, 6479, 11663, 51983, 196559

Offset: 1

Author

Felix Fröhlich, Dec 09 2020

Keywords

• nonn
• hard
• more

Comments

a(1)-a(5) are given on p. 11 in Yaqubi, Fatehizadeh, 2020. According to the authors there are no other terms up to 10^6.

Apparently an erroneous version of A331977.

Included in accordance with OEIS policy of including published but erroneous sequences to serve as pointers to the correct values.

Links

• D. Yaqubi and A. Fatehizadeh, Some results on average of Fibonacci and Lucas sequences, arXiv:2001.11839 [math.CO], 2020.

Crossrefs

Cf. A000045, A111035.

Programs

PARI

is(n) = my(s=sum(i=1, n, fibonacci(i))); lift(Mod(s, n))==0 && lift(Mod(s+fibonacci(n+1), n+1))==0