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A047721 Sum of 10 but no fewer nonzero fourth powers. 2
10, 25, 40, 55, 70, 90, 105, 120, 135, 150, 160, 170, 185, 200, 215, 225, 230, 250, 265, 280, 295, 310, 330, 345, 360, 375, 390, 400, 410, 425, 440, 455, 465, 470, 485, 490, 505, 520, 535, 550, 565, 570, 585, 600, 615, 634, 640, 650, 665, 680, 695, 714, 730 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
PROG
(PARI) upto(n)={my(e=10); my(s=sum(k=1, sqrtint(sqrtint(n)), x^(k^4)) + O(x*x^n)); my(p=s^e, q=(1 + s)^(e-1)); select(k->polcoeff(p, k) && !polcoeff(q, k), [1..n])} \\ Andrew Howroyd, Jul 06 2018
(Python)
from itertools import count, takewhile, combinations_with_replacement as mc
def aupto(lim):
p4 = list(takewhile(lambda x: x <= lim, (i**4 for i in count(1))))
s = [set(sum(c) for c in mc(p4, i) if sum(c) <= lim) for i in range(11)]
ans = s[10]
for i in range(1, 10):
ans -= s[i]
return sorted(ans)
print(aupto(730)) # Michael S. Branicky, Oct 25 2021
CROSSREFS
Sequence in context: A038350 A003344 A345853 * A155576 A269457 A043123
KEYWORD
nonn
AUTHOR
Arlin Anderson (starship1(AT)gmail.com)
STATUS
approved

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Last modified June 23 07:33 EDT 2024. Contains 373629 sequences. (Running on oeis4.)