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 21 results. Next

A046459 Dudeney numbers: integers equal to the sum of the digits of their cubes.

Original entry on oeis.org

0, 1, 8, 17, 18, 26, 27
Offset: 1

Views

Author

Patrick De Geest, Aug 15 1998

Keywords

Comments

This sequence was first found by the French mathematician Claude (Séraphin) Moret-Blanc in 1879. See Le Lionnais page 27 for the last term of this sequence: 27. - Bernard Schott, Dec 07 2012
The name "Dudeney numbers" appears in the October 2018 issue of Mathematics Teacher (see link). - N. J. A. Sloane, Oct 10 2018

Examples

			a(3) = 8 because 8^3 = 512 and 5 + 1 + 2 = 8.
a(7) = 27 because 27^3 = 19683 and 1 + 9 + 6 + 8 + 3 = 27.
		

References

  • H. E. Dudeney, 536 Puzzles & Curious Problems, reprinted by Souvenir Press, London, 1968, p. 36, #120.
  • Italo Ghersi, Matematica dilettevole e curiosa, p. 115, Hoepli, Milano, 1967. [From Vincenzo Librandi, Jan 02 2009]
  • F. Le Lionnais, Les nombres remarquables, Hermann, 1983.
  • J. Roberts, Lure of the Integers, The Mathematical Association of America, 1992, p. 172.
  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 96.

Crossrefs

Programs

  • Magma
    [n: n in [0..100] | &+Intseq(n^3) eq n ]; // Vincenzo Librandi, Sep 16 2015
    
  • Mathematica
    Select[Range[0,30],#==Total[IntegerDigits[#^3]]&] (* Harvey P. Dale, Dec 21 2014 *)
  • PARI
    isok(k)=sumdigits(k^3)==k \\ Patrick De Geest, Dec 10 2024
  • Python
    a = [n for n in range(100) if sum(map(int, str(n ** 3))) == n] # David Radcliffe, Aug 18 2022
    

Extensions

Offset corrected by Arkadiusz Wesolowski, Aug 09 2013

A055565 Sum of digits of n^4.

Original entry on oeis.org

0, 1, 7, 9, 13, 13, 18, 7, 19, 18, 1, 16, 18, 22, 22, 18, 25, 19, 27, 10, 7, 27, 22, 31, 27, 25, 37, 18, 28, 25, 9, 22, 31, 27, 25, 19, 36, 28, 25, 18, 13, 31, 27, 25, 37, 18, 37, 43, 27, 31, 13, 27, 25, 37, 27, 28, 43, 18, 31, 22, 18, 34, 37, 36, 37, 34, 45, 13, 31, 27, 7
Offset: 0

Views

Author

Henry Bottomley, Jun 19 2000

Keywords

Examples

			a(2) = 7 because 2^4 = 16 and 1+6 = 7.
		

Crossrefs

Cf. A000583, A007953, A055570, A055575 (fixed points), A373914.

Programs

  • Maple
    for i from 0 to 200 do printf(`%d,`,add(j, j=convert(i^4, base, 10))) od;
  • Mathematica
    a[n_Integer]:=Apply[Plus, IntegerDigits[n^4]]; Table[a[n], {n, 0, 100}] (* Vincenzo Librandi, Feb 23 2015 *)
  • PARI
    a(n) = sumdigits(n^4); \\ Seiichi Manyama, Nov 16 2021
  • Sage
    [sum((n^4).digits()) for n in (0..70)] # Bruno Berselli, Feb 23 2015
    

Formula

a(n) = A007953(A000583(n)). - Michel Marcus, Feb 23 2015

Extensions

More terms from James Sellers, Jul 04 2000

A055566 Sum of digits of n^5.

Original entry on oeis.org

0, 1, 5, 9, 7, 11, 27, 22, 26, 27, 1, 14, 27, 25, 29, 36, 31, 35, 45, 37, 5, 18, 25, 29, 36, 40, 35, 36, 28, 23, 9, 34, 29, 36, 31, 35, 36, 46, 41, 36, 7, 29, 27, 31, 35, 36, 46, 32, 45, 43, 11, 27, 22, 44, 36, 37, 41, 36, 52, 47, 27, 40, 35, 45, 37, 32, 36, 25, 47, 36, 22, 35
Offset: 0

Views

Author

Henry Bottomley, May 26 2000

Keywords

Examples

			a(2) = 5 because 2^4 = 32 and 3+2 = 5.
Trajectories under the map x->a(x):
1 ->1 ->1 ->1 ->1 ->1 ->1 ->1 ->1 ->..
2 ->5 ->11 ->14 ->29 ->23 ->29 ->23 ->29 ->..
3 ->9 ->27 ->36 ->36 ->36 ->36 ->36 ->36 ->..
4 ->7 ->22 ->25 ->40 ->7 ->22 ->25 ->40 ->..
5 ->11 ->14 ->29 ->23 ->29 ->23 ->29 ->23 ->..
6 ->27 ->36 ->36 ->36 ->36 ->36 ->36 ->36 ->..
7 ->22 ->25 ->40 ->7 ->22 ->25 ->40 ->7 ->..
		

Crossrefs

Programs

  • Maple
    read("transforms") :
    A055566 := proc(n)
            digsum(n^5) ;
    end proc: # R. J. Mathar, Jul 08 2012
  • Mathematica
    Table[Total[IntegerDigits[n^5]],{n,0,80}] (* Harvey P. Dale, Feb 12 2023 *)
  • PARI
    a(n) = sumdigits(n^5); \\ Seiichi Manyama, Nov 16 2021

A070276 Numbers n such that sum of digits of n equals the sum of digits of n^3.

Original entry on oeis.org

0, 1, 8, 10, 80, 100, 171, 378, 468, 487, 577, 585, 586, 684, 800, 1000, 1710, 3780, 4680, 4870, 4877, 5770, 5850, 5851, 5860, 5868, 6840, 8000, 10000, 15877, 17100, 28845, 37800, 46800, 48700, 48770, 57700, 58500, 58510, 58600, 58680, 58968, 59777
Offset: 1

Views

Author

Benoit Cloitre, May 09 2002

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[0,60000],Total[IntegerDigits[#]]==Total[IntegerDigits[ #^3]]&] (* Harvey P. Dale, May 10 2012 *)
  • PARI
    isok(n) = sumdigits(n) == sumdigits(n^3); \\ Michel Marcus, Aug 12 2017

A055567 Sum of digits of n^6.

Original entry on oeis.org

0, 1, 10, 18, 19, 19, 27, 28, 19, 18, 1, 28, 45, 37, 37, 27, 37, 37, 18, 37, 10, 36, 37, 46, 36, 28, 46, 45, 37, 37, 18, 46, 37, 54, 37, 46, 45, 46, 37, 45, 19, 28, 45, 37, 46, 45, 64, 46, 36, 37, 19, 54, 55, 37, 54, 46, 55, 54, 55, 37, 27, 37, 46, 36, 64, 55, 45, 55, 64, 45
Offset: 0

Views

Author

Henry Bottomley, May 26 2000

Keywords

Examples

			a(2) = 10 because 2^6 = 64 and 6+4 = 10.
		

Crossrefs

Programs

  • Mathematica
    DigitSum[Range[0, 100]^6] (* Paolo Xausa, Jul 03 2024 *)
  • PARI
    a(n) = sumdigits(n^6); \\ Seiichi Manyama, Nov 16 2021

A055569 Sum of digits of a(n)^3 is greater than or equal to a(n).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 26, 27
Offset: 0

Views

Author

Henry Bottomley, May 26 2000

Keywords

Examples

			a(4) = 4 because 4^3 = 64 and 6+4 = 10>= 4
		

Crossrefs

Programs

  • Mathematica
    Select[Range[300],Total[IntegerDigits[#^3]]>=#&] (* Harvey P. Dale, Aug 27 2013 *)

A073636 Period 3: repeat [1, 8, 9] ; Digital root of A000578(n) = n^3 for n >= 1.

Original entry on oeis.org

1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9, 1, 8, 9
Offset: 1

Views

Author

Zak Seidov, Sep 01 2002

Keywords

Comments

a(n) is the decimal expansion of 70/37. [Enrique Pérez Herrero, Jul 28 2009]; corrected by David A. Corneth, Jun 30 2016

Crossrefs

Cf. A000578, A004164, A010888, A021596. Digital roots of squares are in A056992.

Programs

  • Magma
    &cat [[1, 8, 9]^^30]; // Wesley Ivan Hurt, Jun 30 2016
  • Maple
    seq(op([1, 8, 9]), n=1..50); # Wesley Ivan Hurt, Jun 30 2016
  • Mathematica
    n=3; su[x_] := Sum[IntegerDigits[x][[i]], {i, Length[IntegerDigits[x]]}]; Table[su[su[su[su[x^n]]]], {x, 100}]
    NestWhile[Total[IntegerDigits[#]] &, #1, # > 9 &] & /@ (Range[87]^3) (* Jayanta Basu, Jul 03 2013 *)

Formula

G.f.: x*(9*x^2+8*x+1)/(1-x^3). - Ant King, Apr 30 2013
From Wesley Ivan Hurt, Jun 30 2016: (Start)
a(n) = a(n-3) for n>3.
a(n) = 6 + 3*cos(2*n*Pi/3) - 7*sin(2*n*Pi/3)/sqrt(3). (End)

Extensions

Decimal expansion fraction corrected by Ant King, Apr 30 2013
Edited: name specified, offset changed from 0 to 1 (according to name), adjusted formula and g.f. for offset 1, digital root link added. - Wolfdieter Lang, Jan 05 2015

A107679 Numbers n such that sum of digits of n^3 is 2^3 = 8.

Original entry on oeis.org

2, 5, 8, 11, 20, 50, 80, 101, 110, 200, 500, 800, 1001, 1010, 1100, 2000, 5000, 8000, 10001, 10010, 10100, 11000, 20000, 50000, 80000, 100001, 100010, 100100, 101000, 110000, 200000, 500000, 800000, 1000001, 1000010, 1000100, 1001000, 1010000, 1100000
Offset: 1

Views

Author

Zak Seidov, Jun 10 2005

Keywords

Crossrefs

Cf. A004164 (sum of digits of cubes), A067075, A159462, A159463.

Programs

  • Magma
    [ n: n in [1..2*10^6] | 8 eq (&+Intseq(n^3)) ]; // Vincenzo Librandi, Aug 13 2017
  • Mathematica
    Do[If[Total[IntegerDigits[m^3]]==8, Print[m]], {m, 2*10^7}] (* Vincenzo Librandi, Aug 13 2017 *)
  • PARI
    isok(n) = sumdigits(n^3) == 8; \\ Michel Marcus, Aug 12 2017
    

Extensions

More terms from Michel Marcus, Oct 09 2013

A235398 Sum of digits of the cubes of prime numbers.

Original entry on oeis.org

8, 9, 8, 10, 8, 19, 17, 28, 17, 26, 28, 19, 26, 28, 17, 35, 26, 28, 19, 26, 28, 28, 35, 35, 28, 8, 28, 17, 28, 35, 28, 26, 26, 37, 35, 28, 46, 28, 35, 35, 35, 37, 44, 37, 35, 46, 37, 37, 35, 37, 35, 35, 37, 26, 44, 35, 35, 28, 28, 26, 37, 35, 37, 17, 37, 26
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Maple
    read("transforms") :
    A235398 := proc(n)
        digsum(ithprime(n)^3) ;
    end proc:
    seq(A235398(n),n=1..40) ; # R. J. Mathar, Jul 19 2024
  • PARI
    a(n) = sumdigits(prime(n)^3); \\ Michel Marcus, Jan 09 2014

Formula

a(n) = A007953(A030078(n)). - R. J. Mathar, Jul 19 2024

A076204 Numbers whose cube has a prime sum of digits.

Original entry on oeis.org

13, 14, 16, 17, 22, 23, 25, 28, 34, 37, 47, 52, 58, 64, 67, 68, 74, 76, 85, 106, 107, 118, 130, 134, 139, 140, 142, 146, 160, 166, 169, 170, 172, 175, 178, 181, 193, 196, 211, 217, 218, 220, 223, 229, 230, 232, 241, 244, 250, 253, 256, 265, 268, 280, 283, 286
Offset: 1

Views

Author

Zak Seidov, Nov 02 2002

Keywords

Crossrefs

Corresponding primes in A109410.

Programs

  • Mathematica
    A076204=Select[Range[500], PrimeQ[Plus@@IntegerDigits[ #^3]]&]

Formula

a(n) = (A109408(n))^(1/3).

Extensions

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 21 2007
Showing 1-10 of 21 results. Next