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A345865 Numbers that are the sum of two cubes in exactly four ways. 4
6963472309248, 12625136269928, 21131226514944, 26059452841000, 55707778473984, 74213505639000, 95773976104625, 101001090159424, 159380205560856, 169049812119552, 174396242861568, 188013752349696, 208475622728000, 300656502205416, 340878679288056 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Differs from A023051 at term 143 because 48988659276962496 = 331954^3 + 231518^3 = 336588^3 + 221424^3 = 342952^3 + 205292^3 = 362753^3 + 107839^3 = 365757^3 + 38787^3.
LINKS
EXAMPLE
12625136269928 is a term because 12625136269928 = 21869^3 + 12939^3 = 22580^3 + 10362^3 = 23066^3 + 7068^3 = 23237^3 + 4275^3.
PROG
(Python)
from itertools import combinations_with_replacement as cwr
from collections import defaultdict
keep = defaultdict(lambda: 0)
power_terms = [x**3 for x in range(1, 1000)]
for pos in cwr(power_terms, 2):
tot = sum(pos)
keep[tot] += 1
rets = sorted([k for k, v in keep.items() if v == 4])
for x in range(len(rets)):
print(rets[x])
CROSSREFS
Sequence in context: A295353 A210588 A023051 * A003826 A127344 A186179
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified April 22 01:34 EDT 2024. Contains 371887 sequences. (Running on oeis4.)