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A341891
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Numbers that are the sum of five fourth powers in nine or more ways.
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7
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619090, 775714, 954979, 1100579, 1179379, 1186834, 1205539, 1243699, 1357315, 1367539, 1373859, 1422595, 1431234, 1436419, 1511299, 1536019, 1574850, 1699234, 1713859, 1734899, 1801459, 1839874, 1858594, 1863859, 1877394, 1880850, 1882579, 1950355, 1951650
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refs;
listen;
history;
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internal format)
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OFFSET
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1,1
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LINKS
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EXAMPLE
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619090 = 1^4 + 2^4 + 18^4 + 22^4 + 23^4
= 1^4 + 3^4 + 4^4 + 8^4 + 28^4
= 1^4 + 11^4 + 14^4 + 22^4 + 24^4
= 2^4 + 2^4 + 8^4 + 17^4 + 27^4
= 2^4 + 13^4 + 13^4 + 18^4 + 26^4
= 3^4 + 6^4 + 12^4 + 16^4 + 27^4
= 4^4 + 12^4 + 14^4 + 23^4 + 23^4
= 9^4 + 12^4 + 16^4 + 21^4 + 24^4
= 14^4 + 16^4 + 18^4 + 19^4 + 23^4
so 619090 is a term.
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PROG
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(Python)
from itertools import combinations_with_replacement as cwr
from collections import defaultdict
keep = defaultdict(lambda: 0)
power_terms = [x**4 for x in range(1, 1000)]
for pos in cwr(power_terms, 5):
tot = sum(pos)
keep[tot] += 1
rets = sorted([k for k, v in keep.items() if v >= 9])
for x in range(len(rets)):
print(rets[x])
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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