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.

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A062045 Positive numbers whose product of digits is 12 times their sum.

Original entry on oeis.org

666, 1479, 1497, 1568, 1586, 1658, 1685, 1749, 1794, 1856, 1865, 1947, 1974, 2349, 2394, 2439, 2446, 2464, 2493, 2644, 2934, 2943, 3249, 3294, 3345, 3354, 3429, 3435, 3453, 3492, 3534, 3543, 3924, 3942, 4179, 4197, 4239, 4246, 4264, 4293, 4329, 4335, 4353, 4392
Offset: 1

Views

Author

Amarnath Murthy, Jun 28 2001

Keywords

Examples

			2349 belongs to the sequence as (2*3*4*9)/(2+3+4+9) = 216/18 = 12.
		

Crossrefs

Programs

  • Mathematica
    okQ[n_]:=Module[{idn=IntegerDigits[n]},Times@@idn/Total[idn]==12]
    Select[Range[10000],okQ] (* Harvey P. Dale, Nov 25 2010 *)
  • PARI
    isok(n) = my(d=digits(n)); vecprod(d)==12*vecsum(d) \\ Mohammed Yaseen, Sep 12 2022
    
  • Python
    from math import prod
    def ok(n): d = list(map(int, str(n))); return prod(d) == 12*sum(d)
    print([k for k in range(1, 4400) if ok(k)]) # Michael S. Branicky, Sep 12 2022

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 06 2001
More terms from Harvey P. Dale, Nov 25 2010
Offset corrected by Mohammed Yaseen, Sep 12 2022

A062384 Positive numbers whose product of digits is 7 times their sum.

Original entry on oeis.org

279, 297, 357, 375, 537, 573, 729, 735, 753, 792, 927, 972, 1447, 1474, 1744, 4147, 4174, 4417, 4471, 4714, 4741, 7144, 7414, 7441, 11367, 11376, 11637, 11673, 11736, 11763, 12247, 12274, 12427, 12472, 12724, 12742, 13167, 13176, 13617, 13671
Offset: 1

Views

Author

Amarnath Murthy, Jun 27 2001

Keywords

Examples

			1447 belongs to the sequence as (1*4*4*7)/(1+4+4+7) = 112/16 = 7.
		

Crossrefs

Programs

  • PARI
    isok(n) = my(d=digits(n)); vecprod(d)==7*vecsum(d) \\ Mohammed Yaseen, Sep 09 2022
    
  • Python
    from math import prod
    def ok(n): d = list(map(int, str(n))); return n > 0 and prod(d) == 7*sum(d)
    print([k for k in range(14000) if ok(k)]) # Michael S. Branicky, Sep 09 2022

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 06 2001

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

A062996 Numbers whose sum of digits is greater than or equal to its product of digits.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 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, 123, 130, 131, 132
Offset: 1

Views

Author

Henry Bottomley, Jun 29 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[150],Total[IntegerDigits[#]]>=Times@@IntegerDigits[#]&] (* Harvey P. Dale, Sep 27 2023 *)
  • PARI
    isok(k)={my(d=digits(k)); vecsum(d) >= vecprod(d)} \\ Harry J. Smith, Aug 15 2009

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

A249334 Numbers for which the digital sum contains the same distinct digits as the digital product.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 22, 99, 123, 132, 213, 231, 312, 321, 1124, 1137, 1142, 1173, 1214, 1241, 1317, 1371, 1412, 1421, 1713, 1731, 2114, 2141, 2411, 3117, 3171, 3344, 3434, 3443, 3711, 4112, 4121, 4211, 4334, 4343, 4433, 7113, 7131, 7311, 11125, 11133
Offset: 1

Views

Author

Jaroslav Krizek, Oct 25 2014

Keywords

Comments

Numbers k such that A007953(k) contains the same distinct digits as A007954(k). (But either of the two may contain some digit(s) more than once.)
Supersequence of A034710 (positive numbers for which the sum of digits is equal to the product of digits).
Union of A034710 and A249335.
The sequence is infinite since, e.g., A002275(n) = (10^n-1)/9 is in the sequence for all n = A002275(k), k>=0; and more generally N(k,d) = A002275(n)-1+d with n = (A002275(k)-1)*d+1, k>0 and 0M. F. Hasler, Oct 29 2014

Examples

			1137 is a term because 1+1+3+7 = 12 and 1*1*3*7 = 21.
3344 is a term because 3+3+4+4=14 has the same (distinct) digits as 3*3*4*4=144.
		

Crossrefs

Programs

  • Magma
    [0] cat [n: n in [1..10^6] | Set(Intseq(&*Intseq(n))) eq Set(Intseq(&+Intseq(n)))];
    
  • Mathematica
    Select[Range[0,12000],Union[IntegerDigits[Total[IntegerDigits[#]]]]==Union[IntegerDigits[Times@@IntegerDigits[#]]]&] (* Harvey P. Dale, Aug 17 2025 *)
  • PARI
    is_A249334(n)=Set(digits(sumdigits(n)))==Set(digits(prod(i=1,#n=digits(n),n[i]))) \\ M. F. Hasler, Oct 29 2014

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

A066307 Nonprimes whose sum of digits is equal to its product of digits.

Original entry on oeis.org

1, 4, 6, 8, 9, 22, 123, 132, 213, 231, 312, 321, 1124, 1142, 1214, 1241, 1412, 1421, 2114, 4112, 4121, 11125, 11133, 11152, 11215, 11222, 11313, 11331, 11512, 11521, 12115, 12122, 12151, 12212, 12221, 13113, 13131, 13311, 15112, 15211, 21115
Offset: 1

Views

Author

Labos Elemer, Dec 13 2001

Keywords

Examples

			321 = 3*107, 3 + 2 + 1 = 6 = 3*2*1.
		

Crossrefs

Composites and 1 from A034710.

Programs

  • Mathematica
    sdpdQ[n_]:=Module[{idn=IntegerDigits[n]},Total[idn]==Times@@idn]; Module[ {upto=25000, cs},cs=Complement[Range[upto],Prime[Range[PrimePi[upto]]]];Select[cs,sdpdQ]] (* Harvey P. Dale, Oct 14 2014 *)
  • PARI
    isok(k) = {if(isprime(k), 0, my(d=digits(k)); vecprod(d) == vecsum(d))} \\ Harry J. Smith, Feb 09 2010

A066308 a(n) = (sum of digits of n) * (product of digits of n).

Original entry on oeis.org

1, 4, 9, 16, 25, 36, 49, 64, 81, 0, 2, 6, 12, 20, 30, 42, 56, 72, 90, 0, 6, 16, 30, 48, 70, 96, 126, 160, 198, 0, 12, 30, 54, 84, 120, 162, 210, 264, 324, 0, 20, 48, 84, 128, 180, 240, 308, 384, 468, 0, 30, 70, 120, 180, 250, 330, 420, 520, 630, 0, 42, 96, 162, 240, 330
Offset: 1

Views

Author

Labos Elemer, Dec 13 2001

Keywords

Comments

a(n) can be greater than, less than, or equal to n; see Example section.

Examples

			For n = 12, a(12) = (1 + 2)*(1*2) = 3*2 = 6 < n;
for n = 19, a(19) = (1 + 9)*(1*9) = 90 > n;
for n = 135, a(135) =(1 + 3 + 5)*(1*3*5) = 135 = n.
		

Crossrefs

Programs

  • Mathematica
    asum[x_] := Apply[Plus, IntegerDigits[x]] apro[x_] := Apply[Times, IntegerDigits[x]] a[n]=asum[n]*apro[n]
    sdpd[n_]:=Module[{idn=IntegerDigits[n]},Total[idn]Times@@idn]; Array[ sdpd,70] (* Harvey P. Dale, Dec 31 2011 *)
  • PARI
    a(n) = my(d = digits(n)); vecsum(d) * vecprod(d); \\ Michel Marcus, Feb 24 2017

Extensions

Edited by Jon E. Schoenfield, Jul 09 2018
Previous Showing 11-20 of 43 results. Next