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.

A046253 Equal to the sum of its nonzero digits raised to its own power.

Original entry on oeis.org

0, 1, 3435, 438579088
Offset: 1

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Author

Patrick De Geest, May 15 1998

Keywords

Comments

A variant of Münchausen numbers, cf. A166623.
The sequence is finite, because the sum can't exceed 9^9*L < 10^9*L, where L is the number of digits, and for L > 10 this is less than the number N >= 10^(L-1). - M. F. Hasler, Oct 01 2024

Examples

			3435 = 3^3 + 4^4 + 3^3 + 5^5.
		

References

  • J. S. Madachy, "Madachy's Mathematical Recreations", Dover N.Y., pp. 163-175.
  • C. A. Pickover, "Keys to Infinity", Wiley 1995, Ch. 22, pp. 169-171.
  • Alfred S. Posamentier, Math Charmers, Tantalizing Tidbits for the Mind, Prometheus Books, NY, 2003, page 37.
  • David Wells, "Curious and Interesting Numbers", Penguin 1988, pp. 169, 190.

Crossrefs

Fixed points of A045512. See also A045503 (includes zero digits).

Programs

  • C
    // See Bailey and Hutchens links
    
  • Mathematica
    Select[Range[0,10000],Total[#^#&/@DeleteCases[IntegerDigits@#,0]]==#&]  (* Giorgos Kalogeropoulos, May 08 2019 *)
  • PARI
    select( {is_A046253(n)=n==A045512(n)}, [0..10^4]) \\ To find the 4th solution, multiply the set by 51817. - M. F. Hasler, Oct 01 2024

A193163 Irregular table read by rows, in which row n lists the factorions in base n, for n >= 2.

Original entry on oeis.org

1, 2, 1, 2, 1, 2, 7, 1, 2, 49, 1, 2, 25, 26, 1, 2, 1, 2, 1, 2, 41282, 1, 2, 145, 40585, 1, 2, 26, 48, 40472, 1, 2, 1, 2, 519326767, 1, 2, 12973363226, 1, 2, 1441, 1442, 1, 2, 2615428934649, 1, 2, 40465, 43153254185213, 43153254226251, 1, 2, 1, 2, 1, 2, 1, 2
Offset: 2

Views

Author

Karl W. Heuer, Aug 06 2011

Keywords

Comments

Because 1 and 2 are factorions in any base, these mark the start of a new row.

Examples

			49 is in row 5 because 49 = 1! + 4! + 4! and is "144" in base 5.
The first few rows are:
1, 2 (binary)
1, 2 (ternary)
1, 2, 7 (quartal)
1, 2, 49 (quintal)
1, 2, 25, 26 (hexal)
1, 2 (heptal)
1, 2 (octal)
1, 2, 41282 (nonal)
1, 2, 145, 40585 (decimal)
1, 2, 26, 48, 40472 (undecimal)
1, 2 (duodecimal)
1, 2, 519326767, etc.
		

Crossrefs

A276170 Let n have j digits {d_j, d_(j-1), ..., d_2, d_1}. Sequence lists numbers n such that n = d_j^b_j + d_(j-1)^b_(j-1) + ... + d_2^b_2 + d_1^b_1 for some permutation {b_j, b_(j-1), ..., b_2, b_1} of the digits.

Original entry on oeis.org

1, 1364, 3435, 4155, 4316, 4355, 17463, 48625, 63725, 78215, 117693, 136775, 137456, 137529, 164726, 184746, 196753, 264719, 326617, 326671, 397612, 423858, 516974, 637395, 652812, 653285, 653957, 687523, 834272, 936627, 1374962, 1617349, 1679812, 1683397, 1683514
Offset: 1

Views

Author

Paolo P. Lava, Aug 23 2016

Keywords

Comments

0^0 is not admitted.
652812 is the first number with two essentially different permutations:
6^1 + 5^8 + 2^5 + 8^6 + 1^2 + 2^2 = 6^2 + 5^8 + 2^1 + 8^6 + 1^5 + 2^2 = 652812.

Examples

			One of the permutations of {1,3,6,4} is {6,1,4,3} and 1^6+3^1+6^4+4^3 = 1364.
		

Crossrefs

Programs

  • Maple
    with(combinat); P:= proc(q) local a,b,c,d,j,k,ok,n;
    for n from 1 to q do ok:=1; d:=ilog10(n)+1; a:=convert(n,base,10); b:=permute(a,d);
    for k from 1 to nops(b) do c:=0; for j from 1 to d do
    if a[j]=0 and b[k][j]=0 then ok:=0; break; else c:=c+a[j]^b[k][j];  fi; od;
    if ok=1 then if c=n then print(n); break; fi; fi; od; od; end: P(10^6);

A276241 Let n have j digits {d_j, d_(j-1), ..., d_2, d_1}. Sequence lists numbers n such that R(n) = d_j^b_j + d_(j-1)^b_(j-1) + ... + d_2^b_2 + d_1^b_1 for some permutation {b_j, b_(j-1), ..., b_2, b_1} of the digits, where R(n) is the digits reverse of n.

Original entry on oeis.org

1, 10, 4631, 5343, 5514, 5534, 6134, 36471, 45130, 51287, 52684, 52736, 85200, 176623, 216793, 218256, 272438, 325786, 357691, 396711, 479615, 512870, 577631, 582356, 593736, 627461, 647481, 654731, 716623, 726639, 759356, 858324, 917462, 925731, 945630, 1075785
Offset: 1

Views

Author

Paolo P. Lava, Aug 25 2016

Keywords

Comments

0^0 is not admitted.

Examples

			One of the permutations of {4,6,3,1} is {3,4,1,6} and 4^3 + 6^4 + 3^1 + 1^6 = 1364 = R(4631).
		

Crossrefs

Programs

  • Maple
    with(combinat):  R:=proc(w) local x, y, z; x:=w; y:=0; for z from 1 to ilog10(x)+1 do y:=10*y+(x mod 10); x:=trunc(x/10); od; y; end:
    P:= proc(q) local a,b,c,d,i,j,k,n,ok,x;
    for n from 1 to q do i:=R(n); x:=convert(n,base,10); d:=ilog10(n)+1; b:=permute(x,d); a:={}; ok:=1;
    for k from 1 to nops(x) do a:={op(a),x{d-k+1}}; od; for k from 1 to nops(b) do c:=0;
    for j from 1 to d do if a{j}=0 and b{k}{j}=0 then ok:=0; break; else c:=c+a{j}^b{k}{j}; fi; od;
    if ok=1 then if i=c then print(n); break; fi; fi; od; od;  end: P(10^12);

A279813 Number of Münchhausen numbers in base n.

Original entry on oeis.org

2, 3, 3, 1, 3, 2, 1, 4, 2, 3, 2, 5, 5, 6, 3, 5, 4, 1, 3, 3, 2, 1, 2, 3, 3, 1, 4, 1, 2, 3, 1, 3, 2, 1
Offset: 2

Views

Author

Eric M. Schmidt, Dec 24 2016

Keywords

Comments

See A166623 for a table of Münchhausen numbers in base n.

Crossrefs

Cf. A166623.
Showing 1-5 of 5 results.