A294354 a(1) = a(3) = a(4) = 2, a(2) = 4; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 4.

2, 4, 2, 2, 4, 6, 4, 6, 6, 4, 8, 8, 8, 12, 6, 6, 16, 12, 6, 18, 8, 14, 12, 12, 16, 16, 16, 16, 16, 24, 10, 20, 20, 24, 14, 22, 18, 24, 14, 22, 22, 36, 12, 26, 26, 36, 16, 28, 28, 28, 24, 28, 32, 30, 28, 32, 32, 32, 32, 32, 32, 48, 16, 34, 38, 36, 26, 56, 20, 40, 34, 44, 30, 50, 42, 40, 32, 60, 22, 50, 42, 42, 44

Offset

1,1

Comments

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

Links

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

Mathematica

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 *)

Prog

(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

Crossrefs

Cf. A005185.

Sequence in context: A117007 A340129 A213433 * A144049 A368435 A058384

Adjacent sequences: A294351 A294352 A294353 * A294355 A294356 A294357

Keyword

nonn

Author

Altug Alkan, Oct 29 2017

Status

approved