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.

A379400 Numbers that can be written in exactly five different ways as a sum of at most nine positive third powers.

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%I A379400 #11 Dec 23 2024 22:02:13
%S A379400 133,145,152,153,159,160,161,163,182,190,192,196,197,198,200,201,209,
%T A379400 218,220,223,225,226,233,234,235,236,237,238,246,248,249,255,258,265,
%U A379400 268,269,274,277,279,292,300,302,304,305,310,311,312,329,331,340,356,364,365,429
%N A379400 Numbers that can be written in exactly five different ways as a sum of at most nine positive third powers.
%C A379400 The 'nine' is not arbitrary. Waring stated that every natural number can be expressed as a sum of at most nine cubes (A002804).
%H A379400 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WaringsProblem.html">Waring's Problem</a>.
%H A379400 Wikipedia, <a href="https://en.wikipedia.org/wiki/Waring%27s_problem">Waring's Problem</a>.
%H A379400 <a href="/index/Su#ssq">Index entries for sequences related to sums of cubes</a>.
%e A379400 133 is in the sequence since 2^3+5^3 = 1^3+1^3+1^3+1^3+1^3+4^3+4^3 = 1^3+2^3+2^3+2^3+3^3+3^3+3^3+3^3 = 1^3+1^3+1^3+1^3+1^3+1^3+1^3+1^3+5^3 = 1^3+1^3+2^3+2^3+2^3+2^3+2^3+3^3+4^3.
%o A379400 (PARI) upto(n) = my(v=vector(n), maxb=sqrtnint(n, 3)); forvec(x=vector(9, i, [0, maxb]), s=sum(i=1, 9, x[i]^3); if(0<s && s<=n, v[s]++); , 1); select(x->x==5, v, 1) \\ _David A. Corneth_, Dec 23 2024
%Y A379400 Cf. A002804, A025453, A379396, A379397, A379398, A379399.
%K A379400 nonn
%O A379400 1,1
%A A379400 _Patrick De Geest_, Dec 23 2024