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A053999 Prime number spiral (clockwise, Northwest spoke).

%I A053999 #23 Feb 19 2022 13:06:55
%S A053999 2,23,97,227,419,661,1009,1427,1879,2437,3083,3803,4637,5519,6481,
%T A053999 7573,8737,9931,11321,12743,14327,15877,17609,19471,21391,23327,25469,
%U A053999 27739,30047,32429,34849,37501,40231,42943,45989,49037,52121,55381,58579
%N A053999 Prime number spiral (clockwise, Northwest spoke).
%C A053999 Largest prime in n-th shell of prime spiral.
%C A053999 Shell 1 comprises the primes 3 5 7 11 13 17 19 23; 3 is lowest, 23 is highest.
%H A053999 Ivan Panchenko, <a href="/A053999/b053999.txt">Table of n, a(n) for n = 0..1000</a>
%F A053999 8-spoke wheel overlays prime number spiral; hub is 2 in shell 0; 8 spokes radiate from this hub; this is Northwest, clockwise.
%F A053999 a(n) = A000040(A016754(n)) . - _R. J. Mathar_, Aug 29 2018
%e A053999 Begin a prime number spiral at shell 0 (prime 2), proceed clockwise, Northwest.
%e A053999 From _Omar E. Pol_, Feb 19 2022: (Start)
%e A053999 The spiral with four terms in every spoke looks like this:
%e A053999 .
%e A053999   227  101--103--107--109--113--127
%e A053999    |     |                       |
%e A053999   223   97   29---31---37---41  131
%e A053999    |     |    |              |   |
%e A053999   211   89   23    3----5   43  137
%e A053999    |     |    |    |    |    |   |
%e A053999   199   83   19    2    7   47  139
%e A053999    |     |    |         |    |   |
%e A053999   197   79   17---13---11   53  149
%e A053999    |     |                   |   |
%e A053999   193   73---71---67---61---59  151
%e A053999    |                             |
%e A053999   191--181--179--173--167--163--157
%e A053999 .
%e A053999 (End)
%t A053999 Table[ Prime[4n^2 + 4n + 1], {n, 0, 40} ]
%Y A053999 Cf. A016754, A054551, A054553, A054555, A054564, A054566, A054566, A054570.
%K A053999 easy,nonn
%O A053999 0,1
%A A053999 _Enoch Haga_ and _G. L. Honaker, Jr._, Apr 10 2000
%E A053999 Edited by _Robert G. Wilson v_, Feb 25 2002