The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A225195 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A225195

Primes p such that (p+nextprime(p))/2 is a perfect square.
(history; published version)

#16 by Harvey P. Dale at Sat Jan 12 19:33:01 EST 2019

STATUS

editing

approved

#15 by Harvey P. Dale at Sat Jan 12 19:32:58 EST 2019

MATHEMATICA

Select[Partition[Prime[Range[10000]], 2, 1], IntegerQ[Sqrt[Mean[#]]]&][[All, 1]] (* Harvey P. Dale, Jan 12 2019 *)

STATUS

approved

editing

#14 by Charles R Greathouse IV at Mon May 13 01:54:23 EDT 2013

LINKS

_Charles R Greathouse IV_, , <a href="/A225195/b225195.txt">Table of n, a(n) for n = 1..5000</a>

Discussion

Mon May 13

01:54

OEIS Server: https://oeis.org/edit/global/1915

#13 by Charles R Greathouse IV at Mon May 13 01:50:10 EDT 2013

LINKS

_Charles R Greathouse IV, _, <a href="/A225195/b225195.txt">Table of n, a(n) for n = 1..5000</a>

Discussion

Mon May 13

01:50

OEIS Server: https://oeis.org/edit/global/1914

#12 by Charles R Greathouse IV at Thu May 09 16:42:40 EDT 2013

STATUS

editing

approved

#11 by Charles R Greathouse IV at Thu May 09 16:42:32 EDT 2013

LINKS

Charles R Greathouse IV, <a href="/A225195/b225195.txt">Table of n, a(n) for n = 1..5000</a>

PROG

(PARI) p=2; forprime(q=3, 1e9, if(issquare((p+q)/2), print1(p", ")); p=q) \\ Charles R Greathouse IV, May 09 2013

KEYWORD

nonn,newchanged

STATUS

approved

editing

#10 by T. D. Noe at Thu May 09 16:03:15 EDT 2013

STATUS

proposed

approved

#9 by Jayanta Basu at Thu May 09 13:56:20 EDT 2013

STATUS

editing

proposed

#8 by Jayanta Basu at Thu May 09 13:54:04 EDT 2013

CROSSREFS

Cf. A000040, A000290., A069495, A075190

STATUS

proposed

editing

Discussion

Thu May 09

13:56

Jayanta Basu: As a matter of fact the sequence of square roots and their respective squares are already there in A069495 and A075190 respectively. Updated the cross-reference.

#7 by Jayanta Basu at Thu May 09 12:12:11 EDT 2013

STATUS

editing

proposed

Discussion

Thu May 09

12:27

T. D. Noe: You should list the square roots in another sequence.

12:47

Jayanta Basu: I would like to do that in a future sequence. Thanks for the suggestion.