1,1

See scatterplots in Links section to observe the distribution of terms.

Table of n, a(n) for n=1..83.

Altug Alkan, Scatterplot of a(n) for n <= 10^5

Altug Alkan, Alternative scatterplot of a(n) for n <= 10^5

Fold[Append[#1, #1[[#2 - #1[[#2 - 1]] ]] + #1[[#2 - #1[[#2 - 2]] ]]] &, {2, 4, 2, 2}, Range[5, 83]] (* Michael De Vlieger, Oct 30 2017 *)

(PARI) q=vector(10^5); q[1]=q[3]=q[4]=2; q[2]=4; for(n=5, #q, q[n] = q[n-q[n-1]]+q[n-q[n-2]]); q

Cf. A005185.

Sequence in context: A210210 A117007 A213433 * A144049 A058384 A255671

Adjacent sequences: A294351 A294352 A294353 * A294355 A294356 A294357

nonn

Altug Alkan, Oct 29 2017

approved