A225892 Numbers of the form p^2 * (p^2 + 1) where p is in A225856.

20, 90, 650, 14762, 28730, 83810, 130682, 280370, 708122, 924482, 1875530, 4881890, 7893290, 12120842, 13849562, 20155610, 25416722, 28403570, 38956322, 47465210, 62750162, 88538690, 104070602, 112561490, 141170042, 163060130, 260160770, 294517082, 352294130

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A071253(A225856(n)). - Amiram Eldar, Feb 23 2021

Example

a(2) = 3^2(3^2+1) = 3^4+3^2 = 90.
a(5) = 13^2(13^2+1) = 13^4+13^2 = 28730.

Mathematica

p = Select[Prime[Range[60]], SquareFreeQ[#^2+1]&]; p^2 * (p^2+1)
#^2 (#^2+1)&/@Select[Prime[Range[50]], SquareFreeQ[#^2+1]&] (* Harvey P. Dale, Jun 17 2022 *)

Crossrefs

Cf. A071253, A225856 (primes p such that p^2+1 is squarefree).

Sequence in context: A344334 A225882 A281768 * A366933 A211140 A200431

Adjacent sequences: A225889 A225890 A225891 * A225893 A225894 A225895

Keyword

nonn

Author

Rafael Parra Machio, May 20 2013

Status

approved