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.

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

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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);