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URL: https://oeis.org/A218207

⇱ A218207 - OEIS

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A218207
Number of n-digit primes of the form (k-1)^2 + k^2.
4
1, 3, 6, 16, 42, 107, 286, 764, 2124, 5917, 17250, 49818, 145429
OFFSET
1,2
FORMULA
a(n) = A218208(n) - A218208(n-1)
MATHEMATICA
n = 0; Table[cnt = 0; While[n++; p = 2*n^2 - 2*n + 1; p < 10^e, If[PrimeQ[p], cnt++]]; n--; cnt, {e, 10}] (* T. D. Noe, Oct 23 2012 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Martin Renner, Oct 23 2012
STATUS
approved