0,1

Steven R. Finch, Triple-Free Sets of Integers [From Steven Finch, Apr 20 2019]

Julien Cassaigne and Paul Zimmermann, Numerical Evaluation of the Strongly Triple-Free Constant (1996). [From Steven Finch, Feb 25 2009]

Julien Cassaigne and Paul Zimmermann, Numerical Evaluation of the Strongly Triple-Free Constant (pdf file, 1996).

Eric Weisstein's World of Mathematics, Triple-Free Set

0.613475269...

0.6134752692022344160180416638... - Steven Finch, Feb 25 2009

f[k_, n_]:=1+Floor[FullSimplify[Log[n/3^k]/Log[2]]]; g[n_]:=Floor[FullSimplify[Log[n]/Log[3]]]; peven[n_]:=Sum[Quotient[f[k, n]+Mod[k+1, 2], 2], {k, 0, g[n]}]; podd[n_]:=Sum[Quotient[f[k, n]+Mod[k, 2], 2], {k, 0, g[n]}]; p[n_]:=Max[peven[n], podd[n]]; v[1]=1; j=1; k=1; n=4001; For[k=2, k=n, k++, If[2*v[k-j]<3^j, v[k]=2*v[k-j], {v[k]=3^j, j++}]]; Sum[p[v[n]]*(1/v[n]-1/v[n+1]), {n, 1, 4000}]/3 (* Steven Finch, Feb 25 2009 *)

Cf. A050295, A050296.

Sequence in context: A218583 A181166 A273191 * A021167 A213204 A085677

Adjacent sequences: A086313 A086314 A086315 * A086317 A086318 A086319

nonn,cons,more

Eric W. Weisstein, Jul 15 2003

More terms from Steven Finch, Feb 25 2009

approved