A331523 a(n) is the least positive k such that A100271(n) - k^3 is a fourth power.

1, 1, 3, 2, 1, 3, 7, 8, 7, 1, 13, 6, 15, 15, 12, 16, 16, 2, 10, 20, 18, 21, 7, 16, 9, 22, 13, 22, 23, 24, 20, 10, 25, 12, 25, 22, 26, 27, 11, 26, 28, 30, 27, 31, 22, 31, 34, 30, 35, 36, 28, 31, 37, 8, 37, 16, 27, 36, 35, 40, 1, 3, 13, 31, 37, 28, 33, 42, 21

Offset

1,3

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, PARI program for A331523

Example

The first terms, alongside A100271(n), are:
  n   a(n)  A100271(n)
  --  ----  ----------------
   1     1     2 = 1^3 + 1^4
   2     1    17 = 1^3 + 2^4
   3     3    43 = 3^3 + 2^4
   4     2    89 = 2^3 + 3^4
   5     1   257 = 1^3 + 4^4
   6     3   283 = 3^3 + 4^4
   7     7   359 = 7^3 + 2^4
   8     8   593 = 8^3 + 3^4
   9     7   599 = 7^3 + 4^4
  10     1  1297 = 1^3 + 6^4

Prog

(PARI) See Links section.

Crossrefs

See A331435 for similar sequences.

Cf. A000583, A100271.

Sequence in context: A078268 A124782 A106611 * A025261 A111572 A046900

Adjacent sequences: A331520 A331521 A331522 * A331524 A331525 A331526

Keyword

nonn

Author

Rémy Sigrist, Jan 19 2020

Status

approved