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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. 6
1, 1, 1, 1, 4, 19, 379, 144019, 20741616379, 430214650034342688004, 185084645104171955001009752069374428191659 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

A quadratic tetranacci sequence.

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

LINKS

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

EXAMPLE

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

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 *)

CROSSREFS

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

Sequence in context: A007411 A276259 A072879 * A080991 A000844 A000863

Adjacent sequences:  A112955 A112956 A112957 * A112959 A112960 A112961

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Jan 02 2006

STATUS

approved

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Last modified February 26 02:19 EST 2020. Contains 332270 sequences. (Running on oeis4.)