[seqfan] A136626,A136627 square spiral prime count

Kevin Ryde user42 at zip.com.au
Sun Feb 24 22:37:06 CET 2013


A136626 and A136627, count of surrounding primes in a square spiral,
have OFFSET=0, but the "EXAMPLE" section describing a(13)=3 would appear
to correspond to OFFSET=1.  Is that right?  Per the example making a(n)
as how many primes surround n in the spiral seems good, so I wonder if
OFFSET=1 was intended.

There might be a typo in the sample a(32) of both A136626 and A136627
too (numbered from offset=1 :).  They show a(32)=2 but I count 3 primes
13,31,59 surrounding 32,

    64 63 62 61 60 59 58 57
    37 36 35 34 33 32 31 56
    38 17 16 15 14 13 30 55
    39 18  5  4  3 12 29 54
    40 19  6  1  2 11 28 53
    41 20  7  8  9 10 27 52
    42 21 22 23 24 25 26 51
    43 44 45 46 47 48 49 50

(A136627=A136626+A010051, so they're the same at n=32 a non-prime.)


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