The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A102821

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A102821

Numbers n for which the square excess of n-th prime is prime.
(history; published version)

#4 by Harvey P. Dale at Sun Jul 06 17:54:59 EDT 2014

STATUS

editing

approved

#3 by Harvey P. Dale at Sun Jul 06 17:54:55 EDT 2014

MATHEMATICA

Select[Range[200], PrimeQ[Prime[#]-Floor[Sqrt[Prime[#]]]^2]&] (* Harvey P. Dale, Jul 06 2014 *)

STATUS

approved

editing

#2 by Charles R Greathouse IV at Sat Oct 12 15:18:06 EDT 2013

AUTHOR

_Olaf Voss (richyfourtythree(AT)yahoo.com), Voß_, Feb 27 2005

Discussion

Sat Oct 12

15:18

OEIS Server: https://oeis.org/edit/global/2013

#1 by N. J. A. Sloane at Sat Apr 09 03:00:00 EDT 2005

NAME

Numbers n for which the square excess of n-th prime is prime.

DATA

2, 4, 5, 8, 9, 13, 14, 15, 19, 20, 23, 27, 28, 30, 35, 36, 37, 38, 39, 46, 49, 56, 57, 67, 68, 69, 71, 81, 83, 86, 93, 94, 96, 98, 107, 108, 109, 111, 112, 113, 114, 124, 128, 138, 139, 142, 144, 155, 156, 157, 158, 159, 160, 161, 162, 173, 178, 182, 192, 195, 196, 199

OFFSET

0,1

EXAMPLE

7 - 2^2 = 3 is the square excess (see A056892) of 7 and it is prime. 7 is the 4th prime, so 4 is in the sequence.

CROSSREFS

Cf. A056892.

KEYWORD

easy,nonn

AUTHOR

Olaf Voss (richyfourtythree(AT)yahoo.com), Feb 27 2005

STATUS

approved