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 1-5 of 5 results.

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

A055577 Numbers k such that the sum of digits of k^6 is equal to k.

Original entry on oeis.org

0, 1, 18, 45, 54, 64
Offset: 1

Views

Author

Henry Bottomley, May 26 2000

Keywords

Examples

			a(2) = 18 because 18^6 = 34012224 and 3+4+0+1+2+2+2+4 = 18
		

Crossrefs

Programs

  • Magma
    [n: n in [0..100] | &+Intseq(n^6) eq n ]; // Vincenzo Librandi, Feb 23 2015
    
  • Mathematica
    Select[Range[0,100],#==Total[IntegerDigits[#^6]]&] (* Harvey P. Dale, Oct 26 2011 *)
  • PARI
    isok(k)=sumdigits(k^6)==k \\ Patrick De Geest, Dec 13 2024
  • Sage
    [n for n in (0..70) if sum((n^6).digits()) == n] # Bruno Berselli, Feb 23 2015
    

A055572 Sum of digits of a(n)^6 is greater than or equal to a(n).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 39, 42, 44, 45, 46, 51, 52, 54, 64
Offset: 0

Views

Author

Henry Bottomley, May 26 2000

Keywords

Examples

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

Crossrefs

A336225 Table read by antidiagonals: T(n, k) = digitsum(n*k) with n >= 0 and k >= 0.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 2, 2, 0, 0, 3, 4, 3, 0, 0, 4, 6, 6, 4, 0, 0, 5, 8, 9, 8, 5, 0, 0, 6, 1, 3, 3, 1, 6, 0, 0, 7, 3, 6, 7, 6, 3, 7, 0, 0, 8, 5, 9, 2, 2, 9, 5, 8, 0, 0, 9, 7, 3, 6, 7, 6, 3, 7, 9, 0, 0, 1, 9, 6, 10, 3, 3, 10, 6, 9, 1, 0, 0, 2, 2, 9, 5, 8, 9, 8, 5, 9, 2, 2, 0
Offset: 0

Views

Author

Stefano Spezia, Jul 12 2020

Keywords

Examples

			The table T(n, k) begins
0   0   0   0   0   0   0   0 ...
0   1   2   3   4   5   6   7 ...
0   2   4   6   8   1   3   5 ...
0   3   6   9   3   6   9   3 ...
0   4   8   3   7   2   6  10 ...
0   5   1   6   2   7   3   8 ...
0   6   3   9   6   3   9   6 ...
0   7   5   3  10   8   6  13 ...
...
		

Crossrefs

Cf. A003991, A004092, A004159 (diagonal), A004164 (digitsum of n^3), A004247, A007953, A055565 (digitsum of n^4), A055566 (digitsum of n^5), A055567 (digitsum of n^6).

Programs

  • Mathematica
    T[n_,k_]:=Total[IntegerDigits[n*k]]; Table[T[n-k,k],{n,0,12},{k,0,n}]//Flatten
  • PARI
    T(n, k) = sumdigits(n*k);

Formula

T(n, k) = A007953(A004247(n, k)).
T(n, 1) = T(1, n) = A007953(n).
T(n, 2) = T(2, n) = A004092(n).
T(n, k) = A007953(A003991(n, k)) for n*k > 0. - Michel Marcus, Jul 13 2020.
Showing 1-5 of 5 results.