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A276416
a(n) = a(n-1)*(1 + a(n-1)/a(n-4)), with a(0) = a(1) = a(2) = a(3) = 1.
1
1, 1, 1, 1, 2, 6, 42, 1806, 1632624, 444245153520, 4698898962968253924720, 12225720633546031105793020748137513851120, 91550929674875028299231929179221527919681972461210779957660001348767546720
OFFSET
0,5
LINKS
FORMULA
0 = a(n)*(a(n+3) - a(n+4)) + a(n+3)*a(n+3) for all n>=0.
A133400(n) = a(n+1)/a(n).
MATHEMATICA
RecurrenceTable[{a[n] == a[n - 1] (1 + a[n - 1]/a[n - 4]), a[0] == a[1] == a[2] == a[3] == 1}, a, {n, 0, 12}] (* Michael De Vlieger, Sep 04 2016 *)
PROG
(Ruby)
def A(m, n)
a = Array.new(m, 1)
ary = [1]
while ary.size < n + 1
break if a[-1] % a[0] > 0
a = *a[1..-1], a[-1] * (1 + a[-1] / a[0])
ary << a[0]
end
ary
end
def A276416(n)
A(4, n)
end
CROSSREFS
Sequence in context: A054377 A349193 A230311 * A007018 A100016 A344562
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 02 2016
STATUS
approved