A112958 a(1) = a(2) = a(3) = a(4) = 1; for n>1: a(n+4) = a(n)^2 + a(n+1)^2 + a(n+2)^2 + a(n+3)^2.

1, 1, 1, 1, 4, 19, 379, 144019, 20741616379, 430214650034342688004, 185084645104171955001009752069374428191659

Offset: 1

Author

Jonathan Vos Post, Jan 02 2006

Keywords

• easy
• nonn

Comments

A quadratic tetranacci sequence.

This is to A000283 as a tetranacci (A000288) is to Fibonacci. Primes in this begin 19, 379.

Examples

			1^2 + 4^2 + 19^2 + 379^2 = 144019.
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..15

Crossrefs

Cf. A000283, A000288, A112957, A112959, A112960.

Programs

Mathematica

RecurrenceTable[{a[1] == a[2] == a[3] == a[4] == 1, a[n] == a[n-1]^2 + a[n-2]^2 + a[n-3]^2 + a[n-4]^2}, a, {n, 15}] (* Vincenzo Librandi, Aug 21 2016 *)