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A344641 Numbers that are the sum of three fifth powers in exactly one way. 4

%I #7 Jul 31 2021 19:39:06

%S 3,34,65,96,245,276,307,487,518,729,1026,1057,1088,1268,1299,1510,

%T 2049,2080,2291,3072,3127,3158,3189,3369,3400,3611,4150,4181,4392,

%U 5173,6251,6282,6493,7274,7778,7809,7840,8020,8051,8262,8801,8832,9043,9375,9824,10902,10933,11144,11925,14026,15553,15584,15795

%N Numbers that are the sum of three fifth powers in exactly one way.

%C Differs from A003348 at term 44785 because 1375298099 = 3^5 + 55^5 + 63^5 = 25^5 + 29^5 + 68^5

%H David Consiglio, Jr., <a href="/A344641/b344641.txt">Table of n, a(n) for n = 1..20000</a>

%e 65 is a term because 65 = 1^5 + 2^5 + 2^5

%o (Python)

%o from itertools import combinations_with_replacement as cwr

%o from collections import defaultdict

%o keep = defaultdict(lambda: 0)

%o power_terms = [x**5 for x in range(1, 500)]

%o for pos in cwr(power_terms, 3):

%o tot = sum(pos)

%o keep[tot] += 1

%o rets = sorted([k for k, v in keep.items() if v == 1])

%o for x in range(len(rets)):

%o print(rets[x])

%Y Cf. A003348, A344188, A344642.

%K nonn

%O 1,1

%A _David Consiglio, Jr._, May 25 2021

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Last modified April 25 10:51 EDT 2024. Contains 371967 sequences. (Running on oeis4.)