A047714 Sums of 3 but no fewer nonzero fourth powers.

3, 18, 33, 48, 83, 98, 113, 163, 178, 243, 258, 273, 288, 338, 353, 418, 513, 528, 593, 627, 642, 657, 707, 722, 768, 787, 882, 897, 962, 1137, 1251, 1266, 1298, 1313, 1328, 1331, 1378, 1393, 1458, 1506, 1553, 1568, 1633, 1808, 1875, 1922, 1937, 2002, 2177

Offset

1,1

Comments

Identical to A003337 for n = 1..87. - Michael S. Branicky, Mar 18 2021

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

A002377(a(n)) = 3. - Robert Israel, Jul 24 2020

Equals A003337 - A344187 - A000583. - Sean A. Irvine, May 15 2021

Maple

N:= 3000: # for terms <= N
F1:= {seq(i^4, i=1..floor(N^(1/4)))}: n1:= nops(F1):
F2:= select(`<=`, {seq(seq(F1[i]+F1[j], i=1..j), j=1..nops(F1))}, N):
F3:= select(`<=`, {seq(seq(s+t, s=F1), t=F2)}, N):
A:= sort(convert(F3 minus (F2 union F1), list)); # Robert Israel, Jul 24 2020

Prog

(Python)
def aupto(lim):
  p1 = set(i**4 for i in range(1, int(lim**.25)+2) if i**4 <= lim)
  p2 = set(a+b for a in p1 for b in p1 if a+b <= lim)
  p3 = set(apb+c for apb in p2 for c in p1 if apb+c <= lim)
  return sorted(p3-p2-p1)
print(aupto(2400)) # Michael S. Branicky, Mar 18 2021

Crossrefs

Cf. A000583, A002377, A336536, A344187.

Subsequence of A003337.

Sequence in context: A190308 A161443 A003337 * A344188 A204192 A108169

Adjacent sequences: A047711 A047712 A047713 * A047715 A047716 A047717

Keyword

nonn

Author

Arlin Anderson (starship1(AT)gmail.com)

Status

approved