login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A242298 Once a number in this sequence is divisible by all numbers 1 to m, subsequent terms are constrained to have the same property; choose the smallest permissible number that is greater than the previous term. 0

%I

%S 1,2,4,6,12,24,36,48,60,120,180,240,300,360,420,840,1680,2520,5040,

%T 7560,10080,12600,15120,17640,20160,22680,25200,27720,55440,83160,

%U 110880,138600,166320,194040,221760,249480,277200,304920,332640,360360,720720,1441440

%N Once a number in this sequence is divisible by all numbers 1 to m, subsequent terms are constrained to have the same property; choose the smallest permissible number that is greater than the previous term.

%C All terms from A095848 belong to this sequence.

%e After 6, none of 7,8,9,10 or 11 are in the sequence since they are not divisible by 1,2 and 3 as 6 is. 12 qualifies, but is now divisible by 1,2,3 and 4, adding a new constraint on subsequent terms.

%e After 24, 30 is not in the sequence because 24 is divisible by all numbers from 1 to 4 and 30 is not divisible by 4. But 36, which is divisible by all of 1 through 4, qualifies.

%e As an irregular table, the n-th row consists of all numbers divisible by A051451(n) but not by A051451(n+1). - _Tom Edgar_, May 22 2014

%o (PARI) consecd(a) = {d = divisors(a); for (i=2, #d, if (d[i] - d[i-1] > 1, return(i-1));); return(a);}

%o findnext(a) = {nconsd = consecd(a); na = a + 1; while (consecd(na) < nconsd, na++); na;}

%o lista(nn) = {a = 1; print1(a, ", "); for (n=1, nn, a = findnext(a); print1(a, ", "););} \\ _Michel Marcus_, May 11 2014

%Y Cf. A051451, A080765.

%K nonn

%O 1,2

%A _J. Lowell_, May 10 2014

%E More terms from _Michel Marcus_, May 11 2014

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 October 21 18:54 EDT 2019. Contains 328308 sequences. (Running on oeis4.)