A372498 Complement of A372477.

8, 11, 14, 15, 18, 22, 23, 29, 32, 35, 38, 40, 41, 45, 47, 51, 53, 54, 55, 58, 59, 62, 66, 68, 69, 71, 74, 77, 78, 80, 83, 87, 88, 92, 95, 96, 98, 99, 105, 106, 107, 113, 115, 116, 118, 119, 123, 125, 126, 128, 130, 131, 134, 135, 137, 138, 141, 143, 149, 150, 153, 154, 155

Offset

1,1

Comments

Sequence is complement of A372477.

This sequence consists of the positive integers that cannot be represented in the form (n*n + k*k - k*n, n*n + k*k - k*n + k - n), n > 0, 0 <= k < n.

Links

Yury Kazakov, Table of n, a(n) for n = 1..1000

N. A. Shikhova, Discussion of a problem on the social network VK (in Russian).

N. A. Shikhova, Illustration for the sequence A372477.

Prog

(Python)
import math
L=20 #tr are terms A372477 below L**2+1
numb=set()
Lmax=math.trunc((1+2*math.sqrt(3*L**2+1))/3)+1
tr=set()
tr.add(1)
for n in range(2, Lmax):
  for k in range(0, n):
    p1=n*n+k*k-k*n
    p2=p1+k-n
    if p1<=L**2:
      tr.add(p1)
    if p2<=L**2:
      tr.add(p2)
for k in  range (1, L**2):
  numb.add(k)
print(sorted(numb-tr))

Crossrefs

Complement of A372477.

Sequence in context: A308562 A254671 A265412 * A345488 A153039 A190208

Adjacent sequences: A372495 A372496 A372497 * A372499 A372500 A372501

Keyword

nonn

Author

Yury Kazakov, S. P. Obukhov, Sean Sun, and N. A. Shikhova, May 03 2024

Status

approved