A217737 a(n) = Fibonacci(n) mod n*(n+1).

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 51, 167, 130, 171, 67, 190, 1, 45, 320, 1, 505, 168, 275, 649, 614, 319, 59, 620, 125, 837, 376, 407, 485, 1296, 1331, 419, 466, 1435, 1231, 1420, 1289, 1653, 830, 2069, 2161, 1344, 1849, 1975, 746, 1167, 1589, 872, 2645, 2205

Offset: 1

Author

Alex Ratushnyak, Mar 22 2013

Keywords

• nonn
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000045, A002708, A121343, A132634, A132636.

Programs

Maple

a:= proc(n) local r, M, p, m; r, M, p, m:=
      <<1|0>, <0|1>>, <<0|1>, <1|1>>, n, n*(n+1);
      do if irem(p, 2, 'p')=1 then r:= r.M mod m fi;
         if p=0 then break fi; M:= M.M mod m
      od; r[1, 2]
    end:
seq(a(n), n=1..100);  # Alois P. Heinz, Nov 26 2016

Mathematica

Table[Mod[Fibonacci[n],n(n+1)],{n,60}] (* Harvey P. Dale, Oct 02 2017 *)

PARI

a(n)=fibonacci(n)%(n*(n+1)) \\ Charles R Greathouse IV, Jun 23 2017

Python

prpr, prev = 0, 1
for i in range(1, 333):
    cur = prpr + prev
    print(str(prev % (i*(i+1))), end=', ')
    prpr, prev = prev, cur

Formula

A000045(n) modulo A002378(n).