OFFSET
1,5
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..16
FORMULA
a(1)=a(2)=a(3)=a(4)=1; for n>4, a(n) = (a(n-1)^2 + a(n-2)^2 + a(n-3)^2 + 1) / a(n-4).
a(n)*a(n+1)*a(n+2)*a(n+3) = (a(n)^2 + a(n+1)^2 + a(n+2)^2 + a(n+3)^2 + 1)/5.
MATHEMATICA
RecurrenceTable[{a[n] == 5 a[n - 1] a[n - 2] a[n - 3] - a[n - 4], a[1] == a[2] == a[3] == a[4] == 1}, a, {n, 12}] (* Michael De Vlieger, Aug 26 2016 *)
PROG
(Ruby)
def A(m, n)
a = Array.new(m, 1)
ary = [1]
while ary.size < n
a = *a[1..-1], *a[1..-1].inject(:*) * (m + 1) - a[0]
ary << a[0]
end
ary
end
def A276259(n)
A(4, n)
end
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 26 2016
STATUS
approved