OFFSET

1,1

FORMULA

a(k) = 0 for k >= 85. - Jinyuan Wang, Aug 26 2019

5 is one of the first starting values that produces rather long sequence until collapses to zero.

MATHEMATICA

a[1] = 5; a[n_] := a[n] = Mod[a[n - 1] * (n - 1), a[n - 1] + n - 1]; Array[a, 100] (* Amiram Eldar, Aug 29 2019 *)

PROG

(Python)

def k(a, b):

return (a*b)%(a+b)

a = [5]

for n in range(1, 100):

a.append(k(a[-1], n))

print(a)

CROSSREFS

KEYWORD

nonn,easy

AUTHOR

Stefan Gog, Aug 23 2019

STATUS

approved