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 1-10 of 14 results. Next

A069537 Multiples of 2 whose digit sum is 2.

Original entry on oeis.org

2, 20, 110, 200, 1010, 1100, 2000, 10010, 10100, 11000, 20000, 100010, 100100, 101000, 110000, 200000, 1000010, 1000100, 1001000, 1010000, 1100000, 2000000, 10000010, 10000100, 10001000, 10010000, 10100000, 11000000, 20000000, 100000010, 100000100, 100001000
Offset: 1

Views

Author

Amarnath Murthy, Apr 01 2002

Keywords

Crossrefs

Cf. A002024, A002260, A088404 (half).
Subsequence of A005349.
Row n=2 of A245062.

Programs

  • PARI
    a(n) = my(r,s=sqrtint((n-1)<<1,&r), x=s+(r>s), y=if(r>s,r-s,r+s)>>1); 10^x + 10^y; \\ Kevin Ryde, Jul 17 2025
  • Python
    from itertools import product
    def agen():
      digits = 1
      while True:
        for i in range(digits-2): yield int("1"+"0"*(digits-3-i)+"1"+"0"*i+"0")
        yield int("2"+"0"*(digits-1))
        digits += 1
    g = agen()
    print([next(g) for i in range(32)]) # Michael S. Branicky, Feb 20 2021
    

Formula

a(n) = 10^A002024(n-1) + 10^A002260(n-1) for n >= 2. - Kevin Ryde, Jul 17 2025

Extensions

Corrected and extended by Ray Chandler, Sep 28 2003

A063997 Multiples of 4 whose digits add to 4.

Original entry on oeis.org

4, 40, 112, 220, 400, 1012, 1120, 1300, 2020, 2200, 3100, 4000, 10012, 10120, 10300, 11020, 11200, 12100, 13000, 20020, 20200, 21100, 22000, 30100, 31000, 40000, 100012, 100120, 100300, 101020, 101200, 102100, 103000, 110020, 110200, 111100
Offset: 1

Views

Author

Lisa O. Coulter (lcoulter(AT)stetson.edu), Sep 06 2001

Keywords

Examples

			4 is an element of the sequence, since 4 is a multiple of 4 the sum of whose digits is 4; 220 is an element of the sequence, since 220 = 4*55 and 2 + 2+ 0 = 4.
		

Crossrefs

Programs

  • Mathematica
    Select[4Range[120000],Total[IntegerDigits[#]]==4&] (* Harvey P. Dale, May 07 2011 *)
  • PARI
    SumDE(x,y)= { local(s); s=0; while (x>9 && sHarry J. Smith, Sep 05 2009

Extensions

More terms from Ray Chandler, Sep 28 2003

A062768 Multiples of 6 such that the sum of the digits is equal to 6.

Original entry on oeis.org

6, 24, 42, 60, 114, 132, 150, 204, 222, 240, 312, 330, 402, 420, 510, 600, 1014, 1032, 1050, 1104, 1122, 1140, 1212, 1230, 1302, 1320, 1410, 1500, 2004, 2022, 2040, 2112, 2130, 2202, 2220, 2310, 2400, 3012, 3030, 3102, 3120, 3210, 3300, 4002, 4020, 4110
Offset: 1

Views

Author

Lisa O Coulter (lisa_coulter(AT)my-deja.com), Jul 17 2001

Keywords

Comments

Even numbers with sum of digits equal to 6 are Harshad numbers (A005349). - Davide Rotondo, Sep 04 2020

Examples

			60 is a member of the sequence since 60 / 6 = 10 and 6 + 0 = 6; 114 is also an element since 114 is divisible by 6 and 1 + 1+ 4 = 6.
		

Crossrefs

Programs

  • ARIBAS
    : var stk: stack; end; minarg := 0; maxarg := 900; n := 6; for k := minarg to maxarg do m := k*n; s := itoa(m); for j := 0 to length(s) - 1 do stack_push(stk,atoi(s[j..j])); end; if sum(stack2array(stk)) = n then write(m," "); end; end;.
  • Mathematica
    Select[ Range[ 6, 4200, 6 ], Plus @@ IntegerDigits[ # ] == 6 & ]

Extensions

More terms from Klaus Brockhaus, Jul 20 2001

A063416 Multiples of 7 whose sum of digits is equal to 7.

Original entry on oeis.org

7, 70, 133, 322, 511, 700, 1015, 1141, 1204, 1330, 2023, 2212, 2401, 3031, 3220, 4102, 5110, 7000, 10024, 10150, 10213, 10402, 11032, 11221, 11410, 12040, 12103, 13111, 13300, 15001, 20041, 20104, 20230, 21112, 21301, 22120, 23002, 24010
Offset: 1

Views

Author

Klaus Brockhaus, Jul 20 2001

Keywords

Comments

Numbers are all 7 mod 63.

Examples

			133 = 19*7 and 1+3+3 = 7, so 133 is a term of this sequence.
		

Crossrefs

Programs

  • ARIBAS
    : var stk: stack; end; minarg := 0; maxarg := 5000; n := 7; for k := minarg to maxarg do m := k*n; s := itoa(m); for j := 0 to length(s) - 1 do stack_push(stk,atoi(s[j..j])); end; if sum(stack2array(stk)) = n then write(m," "); end; end;.
    
  • Mathematica
    Select[Range[7, 25000, 7], Plus @@ IntegerDigits[ # ] == 7 &]
  • PARI
    forstep(m=0, 70000, 7, if(vecsum(digits(m))==7, print1(m, ", "))) \\ Harry J. Smith, Aug 20 2009

A069540 Multiples of 5 with digit sum 5.

Original entry on oeis.org

5, 50, 140, 230, 320, 410, 500, 1040, 1130, 1220, 1310, 1400, 2030, 2120, 2210, 2300, 3020, 3110, 3200, 4010, 4100, 5000, 10040, 10130, 10220, 10310, 10400, 11030, 11120, 11210, 11300, 12020, 12110, 12200, 13010, 13100, 14000, 20030, 20120
Offset: 1

Views

Author

Amarnath Murthy, Apr 01 2002

Keywords

Crossrefs

Programs

  • Mathematica
    Select[5*Range[5000],Total[IntegerDigits[#]]==5&] (* Harvey P. Dale, Nov 08 2017 *)

Extensions

Corrected and extended by Ray Chandler, Sep 28 2003

A069543 Multiples of 8 with digit sum 8.

Original entry on oeis.org

8, 80, 152, 224, 440, 512, 800, 1016, 1160, 1232, 1304, 1520, 2024, 2240, 2312, 2600, 3032, 3104, 3320, 4040, 4112, 4400, 5120, 6200, 8000, 10016, 10160, 10232, 10304, 10520, 11024, 11240, 11312, 11600, 12032, 12104, 12320, 13040, 13112, 13400
Offset: 1

Views

Author

Amarnath Murthy, Apr 01 2002

Keywords

Crossrefs

Extensions

More terms from Ray Chandler, Sep 28 2003

A069536 Smallest multiple of 8 with digit sum n.

Original entry on oeis.org

0, 1000, 200, 120, 40, 32, 24, 16, 8, 72, 64, 56, 48, 184, 176, 96, 88, 296, 288, 496, 488, 696, 688, 896, 888, 1888, 2888, 3888, 4888, 5888, 6888, 7888, 8888, 9888, 19888, 29888, 39888, 49888, 59888, 69888, 79888, 89888, 99888
Offset: 0

Views

Author

Amarnath Murthy, Apr 01 2002

Keywords

Comments

a(25) onwards the pattern is evident.

Crossrefs

Programs

  • Haskell
    a069536 n = a069536_list !! n
    a069536_list = map (* 8) a077495_list
    -- Reinhard Zumkeller, Dec 09 2011

Formula

a(n) = 8 * A077495(n).

Extensions

Missing a(0) inserted by Franklin T. Adams-Watters, Nov 29 2011

A077495 a(n) = smallest k such that the digit sum of 8k is n.

Original entry on oeis.org

0, 125, 25, 15, 5, 4, 3, 2, 1, 9, 8, 7, 6, 23, 22, 12, 11, 37, 36, 62, 61, 87, 86, 112, 111, 236, 361, 486, 611, 736, 861, 986, 1111, 1236, 2486, 3736, 4986, 6236, 7486, 8736, 9986, 11236, 12486, 24986, 37486, 49986, 62486, 74986, 87486, 99986, 112486, 124986
Offset: 0

Views

Author

Amarnath Murthy, Nov 07 2002

Keywords

Crossrefs

Programs

  • Haskell
    import Data.List (elemIndex)
    import Data.Maybe (fromJust)
    a077495 n = fromJust $ elemIndex n $ map a007953 a008590_list
    a077495_list = map a077495 [0..]
    -- Reinhard Zumkeller, Dec 09 2011

Formula

From Robert Israel, Nov 19 2022: (Start) G.f.: -x^24*(985*x^9 - 125*x^8 - 125*x^7 - 125*x^6 - 125*x^5 - 125*x^4 - 125*x^3 - 125*x^2 - 125*x - 111)/((x - 1)*(10*x^9 - 1)) + 112*x^23 + 86*x^22 + 87*x^21 + 61*x^20 + 62*x^19 + 36*x^18 + 37*x^17 + 11*x^16 + 12*x^15 + 22*x^14 + 23*x^13 + 6*x^12 + 7*x^11 + 8*x^10 + 9*x^9 + x^8 + 2*x^7 + 3*x^6 + 4*x^5 + 5*x^4 + 15*x^3 + 25*x^2 + 125*x.
For n >= 24, a(n) = 125*A051885(n-24) + 111. (End)

Extensions

Corrected and extended by Ray Chandler, Aug 03 2003
Missing a(0)=0 added and offset adjusted by Reinhard Zumkeller, Dec 09 2011

A077491 a(n) = smallest k such that 2k has digit sum = n.

Original entry on oeis.org

5, 1, 6, 2, 7, 3, 8, 4, 9, 14, 19, 24, 29, 34, 39, 44, 49, 99, 149, 199, 249, 299, 349, 399, 449, 499, 999, 1499, 1999, 2499, 2999, 3499, 3999, 4499, 4999, 9999, 14999, 19999, 24999, 29999, 34999, 39999, 44999, 49999, 99999, 149999, 199999, 249999, 299999
Offset: 1

Views

Author

Amarnath Murthy, Nov 07 2002

Keywords

Crossrefs

Formula

a(n) = A069532(n)/2.

Extensions

More terms from Ray Chandler, Jul 28 2003

A077492 a(n) = smallest k such that 5k has a digit sum = n.

Original entry on oeis.org

2, 4, 6, 8, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 39, 59, 79, 99, 119, 139, 159, 179, 199, 399, 599, 799, 999, 1199, 1399, 1599, 1799, 1999, 3999, 5999, 7999, 9999, 11999, 13999, 15999, 17999, 19999, 39999, 59999, 79999, 99999, 119999, 139999, 159999, 179999
Offset: 1

Views

Author

Amarnath Murthy, Nov 07 2002

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{1, 0, 0, 0, 0, 0, 0, 0, 10, -10},{2, 4, 6, 8, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19}, 40] (* Georg Fischer, Oct 26 2020 *)

Formula

a(n) = A069534(n)/5.
a(n) = a(n-1) + 10*a(n-9) - 10*a(n-10) for n > 14. - Georg Fischer, Oct 26 2020

Extensions

More terms from Ray Chandler, Jul 28 2003
Showing 1-10 of 14 results. Next