A119746 Sum of previous term and preceding relatively prime terms.

1, 2, 3, 6, 7, 19, 38, 49, 118, 197, 440, 716, 992, 1268, 1544, 1820, 2040, 2313, 9524, 12113, 33210, 45596, 60298, 74944, 89646, 102032, 116678, 129067, 684624, 826077, 1219334, 2189180, 2203807, 7807703, 15615406, 18789059, 50019871, 100039302

Offset

1,2

Links

Table of n, a(n) for n=1..38.

Formula

a(1)=1, a(2)=2, for n>=2, a(n+1) = a(n) + Sum_{1<=k<n, gcd(a(n),a(k))=1} a(k).

Mathematica

s={1, 2}; Do[AppendTo[s, s[[-1]]+Total[Select[s, CoprimeQ[#, s[[-1]]]&]]], {n, 36}]; s (* James C. McMahon, Feb 24 2025 *)

Crossrefs

Cf. A120610.

Sequence in context: A064292 A079663 A064622 * A328023 A265481 A023785

Adjacent sequences: A119743 A119744 A119745 * A119747 A119748 A119749

Keyword

nonn,changed

Author

Franklin T. Adams-Watters, Jun 16 2006

Status

approved