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A046677 Number of primes p of the form p = 4m^2+1 for n^2 < m < (n+1)^2. 0
2, 3, 3, 2, 3, 4, 5, 6, 4, 7, 7, 4, 4, 8, 6, 5, 6, 10, 6, 4, 10, 5, 12, 7, 11, 13, 9, 13, 11, 10, 10, 17, 8, 12, 12, 14, 16, 14, 14, 19, 10, 9, 17, 15, 19, 17, 17, 17, 13, 18, 16, 22, 15, 20, 20, 11, 16, 20, 18, 15, 16, 19, 15, 18, 16, 17, 18, 25, 17, 24, 20, 22, 26, 21, 18, 20, 27 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

P. J. van Albada, Factorization of the numbers n^2+1, Nieuw Arch. Wisk., 16 (1998), pp. 191-197.

LINKS

Table of n, a(n) for n=1..77.

MATHEMATICA

Table[Count[4 #^2 + 1 & /@ Range[n^2 + 1, (n + 1)^2 - 1], _?PrimeQ], {n, 77}] (* Jayanta Basu, Jun 27 2013 *)

CROSSREFS

Sequence in context: A107918 A242392 A002963 * A283104 A109747 A105612

Adjacent sequences:  A046674 A046675 A046676 * A046678 A046679 A046680

KEYWORD

nonn

AUTHOR

Floor van Lamoen

STATUS

approved

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Last modified May 31 19:40 EDT 2020. Contains 334748 sequences. (Running on oeis4.)