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A259615 a(0)=0, a(1)=a(2)=a(3)=a(4)=1; thereafter, a(n) = Sum_{k=1..5} a(n-k-(a(n-k) mod 5)).

%I A259615 #58 Dec 30 2016 05:58:08
%S A259615 0,1,1,1,1,3,4,5,9,9,11,19,23,27,45,87,105,205,401,587,747,1121,1763,
%T A259615 2145,4085,7965,15529,16545,32503,38323,49767,74305,146847,180069,
%U A259615 210427,341745,650987,787109,917411
%N A259615 a(0)=0, a(1)=a(2)=a(3)=a(4)=1; thereafter, a(n) = Sum_{k=1..5} a(n-k-(a(n-k) mod 5)).
%H A259615 Robert G. Wilson v, <a href="/A259615/b259615.txt">Table of n, a(n) for n = 0..1000</a>
%o A259615 (Sage) def first(m):
%o A259615     v=[0,1,1,1,1]
%o A259615     for i in range(5,m+1):
%o A259615       l=0
%o A259615       for s in range(1,5+1):
%o A259615         l += v[i-s-v[i-s]%5]
%o A259615       v.append(l)
%o A259615     return v
%o A259615 (Ruby) def first(m)
%o A259615     v=[0,1,1,1,1]
%o A259615     for i in 5..m-1
%o A259615       i2=0
%o A259615       for j in 1..5
%o A259615         r=i-j
%o A259615         i2 += v[r-v[r]%5]
%o A259615       end
%o A259615       v << i2
%o A259615     end
%o A259615     v
%o A259615 end
%Y A259615 Cf. A000322, A241154 (sequence obtained without mod 5 in formula).
%K A259615 nonn
%O A259615 0,6
%A A259615 _Anders Hellström_, Jun 30 2015