A264763 a(0) = a(1) = 1; for n>1, a(n) = a(n-1) + (a(n-2) mod 5).

1, 1, 2, 3, 5, 8, 8, 11, 14, 15, 19, 19, 23, 27, 30, 32, 32, 34, 36, 40, 41, 41, 42, 43, 45, 48, 48, 51, 54, 55, 59, 59, 63, 67, 70, 72, 72, 74, 76, 80, 81, 81, 82, 83, 85, 88, 88, 91, 94, 95, 99, 99, 103, 107, 110, 112, 112

Offset

0,3

Links

Table of n, a(n) for n=0..56.

Formula

Empirical g.f.: (4*x^12+2*x^11-2*x^10-2*x^9+4*x^8+x^7-2*x^6+x^5+2*x^4+x^3+1) / ((x-1)^2*(x^4+x^3+x^2+x+1)*(x^8-x^6+x^4-x^2+1)). - Colin Barker, Nov 23 2015

Mathematica

a[0] = a[1] = 1; a[n_] := a[n] = a[n - 1] + Mod[a[n - 2], 5]; Table[a@ n, {n, 0, 60}] (* Michael De Vlieger, Nov 24 2015 *)

Prog

(PARI) first(m)=my(v=vector(m)); v[1]=1; v[2]=1; for(i=3, m, v[i]=v[i-1]+v[i-2]%5); v
(Magma) [n le 2 select 1 else Self(n-1)+Self(n-2) mod 5: n in [1..60]]; // Vincenzo Librandi, Nov 24 2015

Crossrefs

Cf. A000045, A003893.

Sequence in context: A141804 A121368 A010073 * A126167 A026260 A371061

Adjacent sequences: A264760 A264761 A264762 * A264764 A264765 A264766

Keyword

nonn,easy

Author

Anders Hellström, Nov 23 2015

Status

approved