login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A073439 A073259(n)=4: the length of iteration-transient leading to n-th 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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 7 19:13 EST 2021. Contains 341928 sequences. (Running on oeis4.)