

A073439


A073259(n)=4: the length of iterationtransient leading to nth composite number equals 4.


0



1, 2, 3, 6, 7, 10, 11, 12, 14, 15, 19, 20, 21, 25, 26, 28, 30, 32, 33, 34, 37, 38, 39, 42, 44, 45, 48, 49, 50, 51, 53, 54, 55, 57, 58, 59, 61, 62, 63, 65, 66, 67, 68, 72, 73, 74, 75, 77, 78, 81, 82, 84, 85, 86, 87, 88, 96, 97, 98, 100, 101, 102, 104, 106, 107, 108, 114, 116, 117, 118, 119, 120, 121, 122, 123, 124, 126, 127, 129, 130, 131, 132, 134, 135, 136, 137, 140, 141, 142, 143, 144, 145, 148
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..92.


EXAMPLE

The sequence is probably finite and given in full. a(1)=1: the fixed point list from m=a(1) to composite[m] is: {1,2,3,4}, the length is 4; largest term seems to be a(4662)=77629, with transient list {77629,85259,85933,85990}. The terms appears in bursts of consecutive integers. A chain of 37 consecutive numbers starts at 28046.


MATHEMATICA

lfp[x_] := Length[FixedPointList[x+PrimePi[ # ]+1&, x]]1 Do[s=lfp[n]; If[Equal[s, 4], Print[n]], {n, 1, 10000000}]


CROSSREFS

Cf. A002808, A073259, A073320.
Sequence in context: A208892 A085397 A307414 * A188084 A242750 A299239
Adjacent sequences: A073436 A073437 A073438 * A073440 A073441 A073442


KEYWORD

nonn


AUTHOR

Labos Elemer, Jul 31 2002


STATUS

approved



