A390178 Numbers that can be represented in more than one way as p^r + q^s with 4 distinct primes p < q, r, s.

79086, 105402, 148998, 159078, 171078, 187686, 211878, 334260, 334638, 401886, 469262, 684272, 848610, 932988, 1068420, 1092752, 1142886, 1449786, 1520118, 1822572, 1853652, 2112540, 2381092, 2478908, 2616540, 2679894, 2699286, 2770038, 2873108, 2985972, 3126060

Offset

1,1

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..150

Formula

a(n) == 0 (mod 2).

Example

a(1) = 79086 = 5^3 + 281^2 = 5^7 + 31^2,
a(2) = 105402 = 17^3 + 317^2 = 41^3 + 191^2.
The smallest number with 3 representations is 6509784 = 23^5 + 271^2 = 47^3 + 2531^2 = 167^3 + 1361^2.

Crossrefs

Subsequence of A390066.

Cf. A053810, A390188.

Sequence in context: A186612 A180973 A264950 * A204570 A385852 A183640

Adjacent sequences: A390175 A390176 A390177 * A390179 A390180 A390181

Keyword

nonn

Author

Hugo Pfoertner, Oct 28 2025

Status

approved