cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A334817 Distinct values of A230399(n) - n.

Original entry on oeis.org

1, 6, 20, 24, 30, 48, 60, 112, 160, 168, 180, 336, 360, 480, 720, 1008, 1080, 1260, 1440, 2100, 2400, 2520, 2880, 3960, 4200, 4680, 5040, 5280, 6720, 7560, 8400, 9240, 12600, 12960, 13440, 13860, 16800, 18480, 20160, 23100, 25200, 27720, 30240, 32760, 37800, 40320, 41580
Offset: 1

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Author

David A. Corneth, May 12 2020

Keywords

Comments

For many terms there are lots of solutions to the equation a(n) = A230399(m) - m. For example there are 5 solutions to 360 = A230399(m) - m, and 5068 solutions to 49008960 = A230399(m) - m.

Examples

			24 is in the sequence as A230399(2) - 2 = 26-2 = 24.
		

Crossrefs

A072528 Table T(n,k) read by rows, giving number of occurrences of the remainder k when n is divided by i=1,2,3,...,n.

Original entry on oeis.org

1, 2, 2, 1, 3, 1, 2, 2, 1, 4, 1, 1, 2, 3, 1, 1, 4, 1, 2, 1, 3, 3, 1, 1, 1, 4, 2, 2, 1, 1, 2, 3, 2, 2, 1, 1, 6, 1, 2, 1, 1, 1, 2, 5, 1, 2, 1, 1, 1, 4, 1, 4, 1, 2, 1, 1, 4, 3, 1, 3, 1, 1, 1, 1, 5, 3, 2, 1, 2, 1, 1, 1, 2, 4, 3, 2, 1, 2, 1, 1, 1, 6, 1, 3, 2, 2, 1, 1, 1, 1, 2, 5, 1, 3, 2, 2, 1, 1, 1, 1, 6, 1, 4, 1, 2
Offset: 1

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Author

Amarnath Murthy, Aug 01 2002

Keywords

Comments

The n-th row adds to n.

Examples

			The table begins
1
2
2 1
3 1
2 2 1
4 1 1
2 3 1 1
4 1 2 1
		

Crossrefs

Cf. A023645 for T(n, 2) and A072527 for T(n, 3).

Formula

Let a(m) be the m-th term in the sequence. Then m=f(n)+k where f(1)=1 and f(n+1)=f(n)+floor((n+1)/2). n is the number being divided by the various i's and k is the remainder under consideration. f(n) has the generating function F(x)= (x(1+2x^2-2x^3))/((1-x)^2(1+x^2)) - Bruce Corrigan (scentman(AT)myfamily.com), Oct 22 2002
G.f. for k-th column: Sum_{m>0} x^((k+1)*m+k)/(1-x^m). - Vladeta Jovovic, Dec 16 2002

Extensions

Edited by Bruce Corrigan (scentman(AT)myfamily.com), Oct 22 2002
More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 25 2003

A230374 The numbers n such that during dividing n by all positive integers not exceeding n the remainder 0 occurs most often.

Original entry on oeis.org

1, 2, 3, 4, 6, 8, 10, 12, 15, 16, 18, 20, 24, 28, 30, 36, 40, 42, 45, 48, 54, 56, 60, 66, 70, 72, 78, 80, 84, 90, 96, 100, 102, 104, 105, 108, 112, 120, 126, 132, 138, 140, 144, 150, 156, 160, 168, 176, 180, 192, 198, 200, 204, 208, 210, 216, 224, 228, 234, 240, 252
Offset: 1

Views

Author

Vladimir Letsko, Oct 17 2013

Keywords

Comments

A natural generalization of highly composite numbers (A002182), which is a subsequence of this sequence.

Examples

			8 is in the sequence because remainder 0 occurs 4 times during division 8 by 1, 2, 3, 4, 5, 6, 7, 8, that is more than other remainders.
9 is not in the sequence because both remainders 0 and 1 occur 3 times during division 9 by 1, 2, 3, 4, 5, 6, 7, 8, 9.
		

Crossrefs

Programs

  • Maple
    rem0:=proc(n) local r,n1,i,mx,f,R;
    n1:=`if`(n mod 2 = 0, n/2-1,(n-1)/2);
    R:=Array(0..n1,fill=1):if n mod 2 = 0 then R[0]:=2 fi:
    for i to n1 do r:=n mod i: R[r]:=R[r]+1 od:
    mx:=R[0]:f:=true:
    for i to n1 do
    if R[i]>= mx then f:=false:break fi od:
    f; end;
    for n do if maxrem(n) then print(n) fi od:
  • Mathematica
    Select[Range[256], (r = (Transpose@Tally@Mod[#, Range@#])[[2]])[[1]] > Max@Rest@r &] (* Ivan Neretin, Nov 13 2016 *)
    zmoQ[n_] := Module[{r = Sort[Tally[Mod[n, Range[n]]]], mx}, mx = Select[r, #[[2]] == Max[r[[All, 2]]] &]; Length[mx] == 1 && mx[[1, 1]] == 0]; Select[ Range[300],zmoQ] (* Harvey P. Dale, Jul 02 2019 *)
  • PARI
    is(n)=v=vector(n+1);for(d=1,n,t=(n%d)+1;v[t]=v[t]+1);nd=v[1];for(i=2,n,if(v[i]>=nd,return(0)));1 \\ Ralf Stephan, Oct 21 2013
Showing 1-3 of 3 results.