OFFSET
0,1
COMMENTS
Largest prime in n-th shell of prime spiral.
Shell 1 comprises the primes 3 5 7 11 13 17 19 23; 3 is lowest, 23 is highest.
LINKS
Ivan Panchenko, Table of n, a(n) for n = 0..1000
FORMULA
8-spoke wheel overlays prime number spiral; hub is 2 in shell 0; 8 spokes radiate from this hub; this is Northwest, clockwise.
EXAMPLE
Begin a prime number spiral at shell 0 (prime 2), proceed clockwise, Northwest.
From Omar E. Pol, Feb 19 2022: (Start)
The spiral with four terms in every spoke looks like this:
.
227 101--103--107--109--113--127
| | |
223 97 29---31---37---41 131
| | | | |
211 89 23 3----5 43 137
| | | | | | |
199 83 19 2 7 47 139
| | | | | |
197 79 17---13---11 53 149
| | | |
193 73---71---67---61---59 151
| |
191--181--179--173--167--163--157
.
(End)
MATHEMATICA
Table[ Prime[4n^2 + 4n + 1], {n, 0, 40} ]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Enoch Haga and G. L. Honaker, Jr., Apr 10 2000
EXTENSIONS
Edited by Robert G. Wilson v, Feb 25 2002
STATUS
approved