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A207801 Permutation of positive numbers. See comments. 3
1, 2, 3, 4, 5, 6, 9, 8, 7, 10, 15, 12, 25, 14, 21, 16, 11, 18, 27, 20, 35, 22, 33, 24, 49, 26, 39, 28, 55, 30, 45, 32, 13, 34, 51, 36, 65, 38, 57, 40, 77, 42, 63, 44, 85, 46, 69, 48, 121, 50, 75, 52, 95, 54, 81, 56, 91, 58, 87, 60, 115, 62, 93, 64, 17, 66, 99, 68, 125, 70, 105, 72, 119, 74 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(1)=1; on places 2,4,6,8,... we put the same numbers, i.e., numbers with the least prime divisor p_1=2; on places 3,7,11,15,... we put numbers with the least prime divisor p_2=3; on places 5,13,21,29,... we put numbers with the least prime divisor p_3=5; etc.

For general description of the order, see comment in A207790.

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..8192

FORMULA

For n>1, a(n) = A083140(1+A209268(n-1)). Equivalently, a(n) = A083221(1+A249725(n-1)). - Ivan Neretin, Apr 30 2016

MATHEMATICA

a = Array[1 &, mx = 74]; cnt = mx - 1; offs = Table[2^(i - 1) + 1, {i, 1, mx}]; n = 1; While[cnt > 0, n++; idx = PrimePi[FactorInteger[n][[1, 1]]]; pos = offs[[idx]]; If[pos > mx, Continue[]]; offs[[idx]] += 2^idx; a[[pos]] = n; cnt--]; a (* Ivan Neretin, May 06 2015 *)

CROSSREFS

Cf. A207790, A207800.

Sequence in context: A246375 A269865 A269387 * A340364 A324106 A252753

Adjacent sequences:  A207798 A207799 A207800 * A207802 A207803 A207804

KEYWORD

nonn

AUTHOR

Vladimir Shevelev and Peter J. C. Moses, Feb 20 2012

STATUS

approved

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Last modified July 31 15:01 EDT 2021. Contains 346374 sequences. (Running on oeis4.)