#
# density records for sspn
#
#   n     density
# ----------------------
    2	0.333333333334
    7	0.344377775803
    8	0.363793731779
    9	0.384319607272
   10	0.405704755854
   11	0.427279020221
   12	0.448324774225
   13	0.458928183324
   14	0.467423308594
   15	0.476620138412
   16	0.485111311844
   17	0.493383579906
   18	0.498860350551
   19	0.503469255399
   20	0.508784479008
   21	0.512873493824
   22	0.516193391561
   23	0.519204579014
   24	0.524239218460
   25	0.528502313915
   26	0.532547717920
   27	0.534616126613
   28	0.538897370118
   29	0.542685989095
   30	0.547450046344
   31	0.549915557590
   32	0.551610103124
   33	0.554829768389
   34	0.557162091000
   35	0.559663930884
   36	0.563818070809
   37	0.568143272135
   39	0.571884148574
   40	0.574357768206
   41	0.574769324712
   42	0.579161673001
   43	0.579973332341
   44	0.581535913861
   46	0.583271502442
   47	0.584191851209
   48	0.584626229956
   49	0.585530701845
   50	0.585747615482
   54	0.587506442360
   55	0.588481885465
   56	0.589763435807
   57	0.591029755805
   58	0.592857845025
   59	0.594549409378
   60	0.595294323849
   61	0.597126825462
   62	0.597759827597
   63	0.598248435034
   64	0.599349591769
   65	0.601476986690
   66	0.602911661036
   67	0.605694046235
   68	0.607270565494
   69	0.608343460740
   70	0.608870712302
   73	0.610428268465
   74	0.610570759614
   76	0.611111751784
   77	0.613564473884
   79	0.613770186690
   81	0.614430459529
   82	0.615424614826
   83	0.615878031154
   84	0.616275246603
   85	0.618446613892
   87	0.619430757654
   90	0.619784442423
   91	0.621060812574
   93	0.623767214268
   96	0.624017587297
   97	0.625352895801
   99	0.625740135999
  100	0.628814922408

2 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 39 40 41 42 43 44 46 47 48 49 50 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 73 74 76 77 79 81 82 83 84 85 87 90 91 93 96 97 99 100

Fit of radii by a power law r = a0*n^a1:
  a0 = 0.85749  a1 = -0.22750