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 1-8 of 8 results.

A062998 Numbers whose sum of digits is less than or equal to its product of digits.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 22, 23, 24, 25, 26, 27, 28, 29, 32, 33, 34, 35, 36, 37, 38, 39, 42, 43, 44, 45, 46, 47, 48, 49, 52, 53, 54, 55, 56, 57, 58, 59, 62, 63, 64, 65, 66, 67, 68, 69, 72, 73, 74, 75, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 88, 89, 92, 93, 94, 95, 96, 97, 98, 99, 123, 124, 125, 126, 127, 128, 129, 132, 133, 134, 135
Offset: 1

Views

Author

Henry Bottomley, Jun 29 2001

Keywords

Crossrefs

Not the same as A037344 (contains 124).

Programs

  • Maple
    isA062998 := proc(n)
            local dgs,s,p ;
            dgs := convert(n,base,10) ;
            s := add(i,i=dgs) ;
            p := mul(i,i=dgs) ;
            if s <= p then
                    true;
            else
                    false;
            end if;
    end proc:
    for n from 2 to 150 do
            if isA062998(n) then
                    printf("%d,",n) ;
            end if;
    end do:   # R. J. Mathar, Aug 14 2025
  • Mathematica
    Select[Range[100],Total[IntegerDigits[#]]<=Times@@IntegerDigits[#]&] (* Harvey P. Dale, Feb 21 2017 *)
  • PARI
    isok(k)={my(d=digits(k)); vecsum(d) <= vecprod(d)} \\ Harry J. Smith, Aug 15 2009
    
  • PARI
    is_A062998(n)={normlp(n=digits(n),1)<=prod(i=1,#n,n[i])} \\ M. F. Hasler, Oct 29 2014

A062329 a(n) = (sum of digits of n) - (product of digits of n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 0, -1, -2, -3, -4, -5, -6, -7, 3, 1, -1, -3, -5, -7, -9, -11, -13, -15, 4, 1, -2, -5, -8, -11, -14, -17, -20, -23, 5, 1, -3, -7, -11, -15, -19, -23, -27, -31, 6, 1, -4, -9, -14, -19, -24, -29, -34, -39, 7, 1, -5, -11, -17, -23, -29, -35, -41, -47, 8, 1, -6, -13, -20, -27
Offset: 0

Views

Author

Amarnath Murthy, Jun 21 2001

Keywords

Examples

			a(23) = 2 + 3 - 2*3 = -1.
a(49) = -(4*9) + (4 + 9) = -36 + 13 = -23.
		

Crossrefs

Programs

  • Mathematica
    a[n_] := (t = IntegerDigits[n]; Plus @@ t - Times @@ t); Table[ a[n], {n, 0, 75}] (* Robert G. Wilson v *)

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 22 2001
Signed version from Henry Bottomley, Jun 29 2001

A062997 Numbers whose sum of digits is strictly greater than its product of digits.

Original entry on oeis.org

10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 30, 31, 40, 41, 50, 51, 60, 61, 70, 71, 80, 81, 90, 91, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 130, 131, 140, 141, 150, 151, 160, 161, 170
Offset: 1

Views

Author

Amarnath Murthy, Jun 27 2001

Keywords

Comments

Every multiple of 10 is a term.

Examples

			118 is a term as 1 + 1 + 8 = 10, 10 > 8 and 8 = 1 * 1 * 8.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[170], (Plus @@ IntegerDigits[ # ]) > (Times @@ IntegerDigits[ # ]) &] (* Alonso del Arte, May 16 2005 *)
  • PARI
    isok(k)={my(d=digits(k)); vecsum(d) > vecprod(d)} \\ Harry J. Smith, Aug 15 2009

Extensions

Extended by Larry Reeves (larryr(AT)acm.org) and Henry Bottomley, Jun 29 2001

A062999 Numbers whose sum of the digits is strictly less than its product of digits.

Original entry on oeis.org

23, 24, 25, 26, 27, 28, 29, 32, 33, 34, 35, 36, 37, 38, 39, 42, 43, 44, 45, 46, 47, 48, 49, 52, 53, 54, 55, 56, 57, 58, 59, 62, 63, 64, 65, 66, 67, 68, 69, 72, 73, 74, 75, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 88, 89, 92, 93, 94, 95, 96, 97, 98, 99, 124, 125, 126, 127
Offset: 1

Views

Author

Henry Bottomley, Jun 29 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[128], (Plus @@ IntegerDigits[ # ]) < (Times @@ IntegerDigits[ # ]) &] (* Alonso del Arte, May 16 2005 *)
  • PARI
    isok(k)={my(d=digits(k)); vecsum(d) < vecprod(d)} \\ Harry J. Smith, Aug 15 2009

A254621 Zerofree numbers having product of digits less than or equal to sum of digits.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 31, 41, 51, 61, 71, 81, 91, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 122, 123, 131, 132, 141, 151, 161, 171, 181, 191, 211, 212, 213, 221, 231, 311, 312, 321, 411
Offset: 1

Views

Author

David A. Corneth, Feb 03 2015

Keywords

Comments

Intersection of A052382 and A062996.
The repunit A002275(k), for k >= 2, appears at position A254622(k-1) + 1. - Wolfdieter Lang, Feb 23 2015

Crossrefs

Programs

  • Maple
    extend:= proc(t, b, d)
      local i,j,m,s,p;
      p:= t[2];
      s:= t[3];
      if s = 0  then if b=2 then j:= 3 else j:= 2 fi
      else  for j from 0 to d-nops(t[1]) while p*b^j <= s + j*b do od
      fi:
      seq([[op(t[1]),b$i],p*b^i,s+i*b],i=0..j-1);
    end proc:
    f:= proc(d)
       local j, b, Res;
       Res:= [seq([[1$j],1,j],j=0..d)];
       for b from 2 to 9 do
         Res:= map(extend,Res,b,d)
       od:
       Res:= map(t -> op(combinat:-permute(t[1])),Res);
       subs(0=NULL,sort(map(t -> add(t[i]*10^(i-1),i=1..nops(t)), Res)));
    end proc:
    f(5); # Robert Israel, May 19 2015
  • Mathematica
    m[w_] := Flatten@Table[i, {i,9}, {w[[i]]}]; a[upd_] := Union@ Flatten@ Table[ FromDigits /@ Flatten[Permutations /@ m /@ Select[ Flatten[ Permutations /@ (IntegerPartitions[d + 9, {9}, Range[d + 1]] - 1), 1], Times @@ (Range[9]^#) <= Total[# Range[9]] &], 1], {d,  upd}]; a[12] (* terms with up to 12 digits, Giovanni Resta, May 19 2015 *)
    zfnQ[n_]:=Module[{idn=IntegerDigits[n]},FreeQ[idn,0]&&Times@@idn <= Total[ idn]]; Select[Range[500],zfnQ] (* Harvey P. Dale, Jun 29 2019 *)
  • PARI
    is(n)={my(d=digits(n));my(p=prod(i=1,#d,d[i])); 0 < p && p<=vecsum(d) } \\ David A. Corneth, May 15 2015

A254622 Number of zerofree positive integers of at most n digits having product of digits less than or equal to sum of digits.

Original entry on oeis.org

9, 27, 61, 124, 255, 474, 860, 1597, 2726, 4232, 6741, 10391, 16177, 24480, 34926, 47875, 65896, 92255, 139262, 198988, 271642, 357674, 474239, 609442, 773493, 1029477, 1404094, 1857856, 2392385, 3169652, 4059322, 5102419, 6482700, 8041992
Offset: 1

Views

Author

David A. Corneth, Feb 03 2015

Keywords

Comments

See A254621 for the numbers with this property. - Wolfdieter Lang, Feb 23 2015

Crossrefs

A274125 Numbers having digits in nondecreasing order and sum of digits greater than or equal to the product of digits.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 22, 111, 112, 113, 114, 115, 116, 117, 118, 119, 122, 123, 1111, 1112, 1113, 1114, 1115, 1116, 1117, 1118, 1119, 1122, 1123, 1124, 11111, 11112, 11113, 11114, 11115, 11116, 11117, 11118, 11119, 11122
Offset: 1

Views

Author

David A. Corneth, Jun 10 2016

Keywords

Comments

Intersection of A062996 and A009994. Permuting the digits of the terms of this sequence gives A254621. Permutations of digits can be found in A261370. The union of A254621 and A011540 is A062996.

Crossrefs

Programs

  • Mathematica
    upto[nd_] := Sort[FromDigits /@ Reverse /@ Select[ Flatten[ IntegerPartitions[#, nd, Range@ 9] & /@ Range[9 nd], 1], Times @@ # <= Plus @@ # &]]; upto[8] (* Giovanni Resta, Jun 20 2016 *)
  • PARI
    is(n) = my(d=digits(n)); prod(i=1, #d, d[i]) <= vecsum(d) && vecsort(d) == d

A274126 Numbers with digits larger than 1 sorted by product of digits minus sum of digits, then by size.

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 8, 9, 22, 23, 24, 222, 25, 33, 26, 27, 34, 223, 28, 29, 35, 44, 224, 2222, 36, 233, 37, 45, 225, 38, 46, 226, 39, 55, 234, 2223, 47, 227, 333, 56, 48, 228, 235, 244, 2224, 22222, 49, 57, 229, 66, 236, 334, 2233, 58, 67, 245, 2225, 237, 59, 68, 335
Offset: 1

Views

Author

David A. Corneth, Jun 10 2016

Keywords

Comments

Let PS(n) be product of digits of n minus sum of digits of n (=-A062329(n)). Then a(n) is PS(A037344(m)) ordered by PS(n) for values of m such that A037344 has its digits in nondecreasing order. If PS(m) some nonzero term m of A002276 exceed some bound, all positive integers t larger than that term without zeros and ones exceed have a larger value for PS(t).
Prepending -A062329(a(n)) or more ones before a(n) gives terms of A274125.
Permuting digits of A274125 gives A254621. Permutations of digits can be found in A261370. The union of A254621 and A011540 is A062996. The b-file lists terms having PS(n) <= 10^6.

Examples

			Suppose we want to order the nondecreasing integers without zeros and ones up to PS(m) = 50. We see that 222222 has PS(222222) = 52, so we only have to check such nondecreasing integers up to 222222. Not all of those must be checked, which is used in the program.
25 is a term. Prepending PS(25) = -A062329(25) = 3 ones before 25 gives 11125, which is a term of A274125. Permuting digits of 11125 gives for example 12511, which is a term of A254621.
		

Crossrefs

Programs

  • PARI
    See program in link "PARI program".
Showing 1-8 of 8 results.