A129282 a(0)=1; for n > 1, a(n) = a(n-1) + (the largest value of gcd(a(k),n) for 0 <= k <= n-1).

1, 2, 4, 5, 9, 14, 17, 24, 32, 41, 46, 47, 59, 60, 74, 89, 105, 122, 131, 132, 152, 173, 195, 218, 242, 247, 260, 269, 283, 284, 314, 315, 347, 380, 397, 432, 468, 505, 543, 582, 602, 643, 664, 707, 751, 796, 842, 889, 937, 944, 954, 971, 1023, 1076, 1130, 1141

Offset

0,2

Links

Ivan Neretin, Table of n, a(n) for n = 0..10000

Example

For those k where 0 <= k <= 9, gcd(a(3),10) = 5 is the largest value for a gcd(a(k),10). So a(10) = a(9) + 5 = 46.
For those k where 0 <= k <= 11, gcd(a(7),12) = 12 is the largest value for a gcd(a(k),12). So a(12) = a(11) + 12 = 59.

Maple

a[0]:=1: for n from 1 to 70 do a[n]:=a[n-1]+max((seq(gcd(a[k], n), k=0..n-1))) od: seq(a[n], n=0..70); # Emeric Deutsch, Apr 11 2007

Mathematica

Fold[Append[#1, #1[[-1]] + Max@GCD[#1, #2]] &, {1}, Range[55]] (* Ivan Neretin, Oct 24 2018 *)

Crossrefs

Cf. A129281.

Sequence in context: A118550 A126697 A162406 * A073153 A073154 A362609

Adjacent sequences: A129279 A129280 A129281 * A129283 A129284 A129285

Keyword

nonn

Author

Leroy Quet, Apr 07 2007

Extensions

More terms from Emeric Deutsch, Apr 11 2007

Status

approved