A007951 Ternary sieve: delete every 3rd number, then every 9th, 27th, etc.

1, 2, 4, 5, 7, 8, 10, 11, 14, 16, 17, 19, 20, 22, 23, 25, 28, 29, 31, 32, 34, 35, 37, 38, 41, 43, 46, 47, 49, 50, 52, 55, 56, 58, 59, 61, 62, 64, 65, 68, 70, 71, 73, 74, 76, 77, 79, 82, 83, 85, 86, 88, 91, 92, 95, 97, 98, 100, 101, 103, 104, 106, 109, 110, 112, 113, 115, 116, 118

Offset

1,2

Comments

Smarandache calls this a "trinary" sieve. - N. J. A. Sloane, Jan 03 2020

The asymptotic density of this sequence is Product_{k>=1} (1 - 1/3^k) = 0.560126... (A100220). - Amiram Eldar, Mar 21 2021

Links

Rémy Sigrist, Table of n, a(n) for n = 1..25000

Florentin Smarandache, Only Problems, Not Solutions!, 4th ed., 1993; Problem 96.

Index entries for sequences generated by sieves

Prog

(PARI) v = List([1..118]); t=3; while (#v>=t, forstep (k=#v\t, 1, -1, listpop(v, k*t); ); t*=3; ); print (v) \\ Rémy Sigrist, Jan 05 2020

Crossrefs

Cf. A007950, A092418, A100220.

Sequence in context: A215099 A022768 A229973 * A237590 A207336 A213539

Adjacent sequences: A007948 A007949 A007950 * A007952 A007953 A007954

Keyword

nonn

Author

R. Muller

Status

approved