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.

A332096 Irregular table where T(n,m) = min_{A subset {1..m-1}} |m^n - Sum_{x in A} x^n|, for 1 <= m <= A332098(n) = largest m for which this is nonzero.

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%I A332096 #13 Aug 01 2020 11:40:32
%S A332096 1,1,1,3,4,2,0,1,0,1,1,7,18,28,25,0,1,8,0,7,1,1,15,64,158,271,317,126,
%T A332096 45,17,59,14,2,15,3,0,2,1,2,1,2,2,2,1,2,0,2,0,1,0,0,0,1,0,1,0,1,0,1,0,
%U A332096 1,0,1,0,1,1,31,210,748,1825,3351,4606,3760,398,131,299,0,318,0,8
%N A332096 Irregular table where T(n,m) = min_{A subset {1..m-1}} |m^n - Sum_{x in A} x^n|, for 1 <= m <= A332098(n) = largest m for which this is nonzero.
%C A332096 It is known (Sprague 1948, cf. A001661) that for any n, only a finite number of positive integers are not the sum of distinct positive n-th powers. Therefore each row is finite, their lengths are given by A332098.
%C A332096 The number of nonzero terms in row n is A332066(n).
%C A332096 The column of the first zero (exact solution m^n = Sum_{x in A} x^n) in each row is given by A030052, unless A030052(n) = A332066(n) + 1 = A332098(n) + 1.
%H A332096 R. Sprague, <a href="https://doi.org/10.1007/BF01185779">Über Zerlegungen in n-te Potenzen mit lauter verschiedenen Grundzahlen</a>, Math. Z. 51 (1948) 466-468.
%F A332096 For all n and m, T(n,m) <= A332097(n) = T(n,m*) with m* = A078607(n).
%F A332096 For m <= m* + 1, T(n,m) = m^n - Sum_{0 < x < m} x^n.
%e A332096 The table reads:
%e A332096   n\ m=1   2    3    4     5     6     7     8    9   10   11  12   13
%e A332096 ----+--------------------------------------------------------------------------
%e A332096   1 |  1   1                                                  (A332098(1) = 2.)
%e A332096   2 |  1   3    4    2     0     1     0     1                (A332098(2) = 8.)
%e A332096   3 |  1   7   18   28    25     0     1     8    0    7    1
%e A332096   4 |  1  15   64  158   271   317   126    45   17   59   14   2   15  3  0 ...
%e A332096   5 |  1  31  210  748  1825  3351  4606  3760  398  131  299   0  318  0  8 ...
%e A332096 The first column is all ones (A000012), since {1..m-1} = {} for m = 1.
%e A332096 The second column is 2^n - 1 = A000225 \ {0}, since {1..m-1} = {1} for m = 2.
%e A332096 The third column is 3^n - 2^n - 1 = |A083321(n)| for n > 1.
%o A332096 (PARI) A332096(n,m,r=0)={if(r, (m<2||r<2^(n-1)) && return(r-1); my(E, t=1); while(m^n>=r, E=m--); E=abs(r-(m+!!E)^n); for(a=2,m, if(r<t+=a^n, t=a-1; break)); t>=m && return(min(E,r-t)); while(m>=t && E, E=min(self()(n,m-1,r-m^n),E); E && E=min(self()(n,m-=1,r),E)); E, m < n/log(2)+1.5, m^n-sum(x=1,m-1,x^n), self()(n,m-1,m^n))}
%Y A332096 Cf. A001661, A332098, A332066, A030052, A332097, A078607.
%Y A332096 Cf. A000012, A000225, A083321.
%K A332096 nonn
%O A332096 1,4
%A A332096 _M. F. Hasler_, Jul 20 2020