A276126 a(0) = 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+a(n-4)^2+a(n-1)*a(n-2)*a(n-3)*a(n-4) ) / a(n-5).
1, 1, 1, 1, 1, 5, 33, 1281, 1853441, 3826997739521, 2989151785658720873470945, 271581474754155314350055167823358355425497243141, 57581776430597685625970981157448022010386123824977761496513036956000541901241585948341716033
Offset: 0
Keywords
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..15
Programs
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Mathematica
nxt[{a_,b_,c_,d_,e_}]:={b,c,d,e,(e^2+d^2+c^2+b^2+e*d*c*b)/a}; NestList[nxt,{1,1,1,1,1},15][[All,1]] (* Harvey P. Dale, Aug 08 2022 *) -
Ruby
def A(m, n) a = Array.new(m, 1) ary = [1] while ary.size < n + 1 i = a[1..-1].inject(0){|s, i| s + i * i} + a[1..-1].inject(:*) break if i % a[0] > 0 a = *a[1..-1], i / a[0] ary << a[0] end ary end def A276126(n) A(5, n) end
Formula
a(n) = 10*a(n-1)*a(n-2)*a(n-3)*a(n-4) - a(n-1)*a(n-2)*a(n-3) - a(n-2)*a(n-3)*a(n-4) - a(n-3)*a(n-4)*a(n-1) - a(n-4)*a(n-1)*a(n-2) - a(n-5).