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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A374736 a(n) is the least number of the form k*n for some k > 0 that can be added to n without carries in decimal.

Original entry on oeis.org

0, 1, 2, 3, 4, 10, 12, 21, 40, 90, 10, 11, 12, 13, 14, 30, 32, 51, 180, 380, 20, 21, 22, 23, 24, 50, 52, 162, 140, 870, 30, 31, 32, 33, 34, 140, 252, 111, 760, 1560, 40, 41, 42, 43, 44, 450, 230, 141, 240, 2450, 100, 102, 104, 106, 324, 110, 112, 342, 1740
Offset: 0

Views

Author

Rémy Sigrist, Jul 18 2024

Keywords

Examples

			For n = 8:
- 1*8 = 8; computing 8 + 8 requires a carry,
- 2*8 = 16; computing 8 + 16 requires a carry,
- 3*8 = 24; computing 8 + 24 requires a carry,
- 4*8 = 32; computing 8 + 32 requires a carry,
- 5*8 = 40; computing 8 + 40 does not require a carry,
- so a(8) = 40.
		

Crossrefs

Cf. A007091, A261892 (analog for binary), A353624 (analog for balanced ternary), A374735.

Programs

  • PARI
    a(n, base = 10) = { for (k = 1, oo, if (sumdigits((k+1)*n, base) == sumdigits(n, base) + sumdigits(k*n, base), return (k*n); ); ); }
    
  • Python
    from itertools import count
    def A374736(n):
        s = list(map(int,str(n)[::-1]))
        return next(k for k in count(n,n) if all(a+b<=9 for a, b in zip(s,map(int,str(k)[::-1])))) # Chai Wah Wu, Jul 19 2024

Formula

a(n) = A374735(n) * n.
a(n) = n iff n belongs to A007091.
a(10*n) = 10*a(n).

A001740 Squares written in base 5.

Original entry on oeis.org

0, 1, 4, 14, 31, 100, 121, 144, 224, 311, 400, 441, 1034, 1134, 1241, 1400, 2011, 2124, 2244, 2421, 3100, 3231, 3414, 4104, 4301, 10000, 10201, 10404, 11114, 11331, 12100, 12321, 13044, 13324, 14111, 14400, 20141, 20434, 21234, 22041, 22400, 23211, 24024
Offset: 0

Views

Author

Keywords

Programs

  • Mathematica
    Table[FromDigits[IntegerDigits[n^2, 5]], {n, 0, 50}] (* T. D. Noe, Aug 10 2012 *)

Formula

a(n) = A007091(A000290(n)). - Jason Kimberley, Dec 13 2012

A004635 Cubes written in base 5.

Original entry on oeis.org

1, 13, 102, 224, 1000, 1331, 2333, 4022, 10404, 13000, 20311, 23403, 32242, 41434, 102000, 112341, 124123, 141312, 204414, 224000, 244021, 320043, 342132, 420244, 1000000, 1030301, 1112213, 1200302, 1240024, 1331000, 1423131, 2022033, 2122222, 2224204
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    [Seqint(Intseq(n^3, 5)): n in [1..30]]; // Vincenzo Librandi, Oct 15 2015
    
  • Mathematica
    Table[FromDigits[IntegerDigits[n^3, 5]], {n, 35}] (* Vincenzo Librandi, Oct 15 2015 *)
  • PARI
    for(n=1,30, print1(fromdigits(digits(n^3, 5)), ", ")) \\ G. C. Greubel, Sep 10 2018

Formula

a(n) = A007091(n^3) = A007091(A000578(n)). - Michel Marcus, Oct 15 2015

Extensions

Changed offset and more terms from Vincenzo Librandi, Oct 15 2015

A023061 Positive numbers k such that k and 2*k are anagrams in base 5 (written in base 5).

Original entry on oeis.org

13, 130, 143, 1300, 1313, 1430, 1443, 13000, 13013, 13130, 13143, 14300, 14313, 14430, 14443, 102342, 103242, 120234, 120324, 130000, 130013, 130130, 130143, 131300, 131313, 131430, 131443, 143000, 143013, 143130, 143143, 144300, 144313
Offset: 1

Views

Author

Keywords

Comments

From Robert Israel, Aug 08 2018: (Start)
The concatenation of two terms is a term.
If a*10^m + b is a term, where b < (2/9)*10^m, then a*10^k+b is a term for all k > m. (End)

Crossrefs

Cf. A007091.

Programs

  • Maple
    f:= proc(n) local L, M;
       L:= convert(n, base, 5);
       M:= convert(2*n, base, 5);
       if sort(L) = sort(M) then add(L[i]*10^(i-1), i=1..nops(L)) else NULL fi
    end proc:
    map(f, [$1..10000]); # Robert Israel, Aug 08 2018
  • Mathematica
    FromDigits[IntegerDigits[#, 5]] & /@ Select[Range[10000], SameQ @@ Sort /@ IntegerDigits[{#, 2*#}, 5] &] (* Amiram Eldar, Aug 06 2025 *)

A023062 Positive numbers k such that k and 3*k are anagrams in base 5 (written in base 5).

Original entry on oeis.org

1032, 1234, 10032, 10320, 10322, 10432, 11402, 12014, 12234, 12340, 12344, 12434, 100032, 100320, 100322, 100432, 101343, 103200, 103220, 103222, 103321, 104320, 104322, 104432, 110332, 112334, 114002, 114020, 114022, 114402, 120014, 120140
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A007091.

Programs

  • Mathematica
    FromDigits[IntegerDigits[#, 5]] & /@ Select[Range[10000], SameQ @@ Sort /@ IntegerDigits[{#, 3*#}, 5] &] (* Amiram Eldar, Aug 06 2025 *)

A023063 Positive numbers k such that k and 4*k are anagrams in base 5 (written in base 5).

Original entry on oeis.org

1034, 10034, 10340, 10344, 10434, 100034, 100340, 100344, 100434, 102243, 102342, 102423, 103400, 103440, 103444, 104340, 104344, 104434, 1000034, 1000340, 1000344, 1000434, 1002243, 1002342, 1002423, 1003400, 1003440, 1003444, 1004340
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A007091.

Programs

  • Mathematica
    FromDigits[IntegerDigits[#, 5]] & /@ Select[Range[30000], SameQ @@ Sort /@ IntegerDigits[{#, 4*#}, 5] &] (* Amiram Eldar, Aug 06 2025 *)

A031473 Numbers whose base-5 representation has 3 more 0's than 4's.

Original entry on oeis.org

125, 250, 375, 626, 627, 628, 630, 635, 640, 650, 675, 700, 750, 875, 1000, 1251, 1252, 1253, 1255, 1260, 1265, 1275, 1300, 1325, 1375, 1500, 1625, 1876, 1877, 1878, 1880, 1885, 1890, 1900, 1925, 1950, 2000, 2125, 2250
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A007091.

Programs

  • Mathematica
    Select[Range[2300],DigitCount[#,5,0]==DigitCount[#,5,4]+3&] (* Harvey P. Dale, Jul 23 2012 *)

A031476 Numbers whose base-5 representation has 3 fewer 0's than 4's.

Original entry on oeis.org

124, 249, 374, 499, 549, 574, 599, 609, 614, 619, 621, 622, 623, 874, 999, 1124, 1174, 1199, 1224, 1234, 1239, 1244, 1246, 1247, 1248, 1499, 1624, 1749, 1799, 1824, 1849, 1859, 1864, 1869, 1871, 1872, 1873, 2124, 2249
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A007091.

A031957 Numbers with exactly three distinct base-5 digits.

Original entry on oeis.org

27, 28, 29, 35, 38, 39, 40, 42, 44, 45, 47, 48, 51, 53, 54, 55, 58, 59, 65, 66, 69, 70, 71, 73, 76, 77, 79, 80, 82, 84, 85, 86, 89, 95, 96, 97, 101, 102, 103, 105, 107, 108, 110, 111, 113, 115, 116, 117, 127, 128, 129, 132, 133, 134
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A007091.

A032940 Numbers whose base-5 representation Sum_{i=0..m} d(i)*5^(m-i) has d(i)=0 for all odd i.

Original entry on oeis.org

1, 2, 3, 4, 5, 10, 15, 20, 25, 26, 27, 28, 29, 50, 51, 52, 53, 54, 75, 76, 77, 78, 79, 100, 101, 102, 103, 104, 125, 130, 135, 140, 145, 250, 255, 260, 265, 270, 375, 380, 385, 390, 395, 500, 505, 510, 515, 520, 625, 626, 627, 628, 629
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A007091 (numbers in base 5).

Programs

  • Maple
    f:= proc(n,j) local L,m;
      L:= convert(n,base,5);
      m:= nops(L);
      j*add(L[i+1]*5^(2*i),i=0..m-1)
    end proc:
    seq(seq(seq(f(n,j),n=5^k..5^(k+1)-1),j=[1,5]),k=0..2); # Robert Israel, Nov 15 2020

Extensions

Definition corrected by Robert Israel, Nov 15 2020
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