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Revision History for A226599

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Showing entries 1-10 | older changes

A226599

Numbers which are the sum of two squared primes in exactly four ways (ignoring order).
(history; published version)

#17 by Susanna Cuyler at Thu Sep 20 00:30:43 EDT 2018

STATUS

proposed

approved

#16 by Jon E. Schoenfield at Wed Sep 19 21:54:44 EDT 2018

STATUS

editing

proposed

#15 by Jon E. Schoenfield at Wed Sep 19 21:54:42 EDT 2018

CROSSREFS

Cf. A045636 (sum of two prime squares squared primes is a superset).

STATUS

approved

editing

#14 by T. D. Noe at Sat Jun 15 01:53:12 EDT 2013

STATUS

editing

approved

#13 by T. D. Noe at Sat Jun 15 01:53:02 EDT 2013

COMMENTS

Suggestion: All It appears that all first differences are divisible by 24. - Zak Seidov, Jun 14 2013

STATUS

proposed

editing

#12 by Jean-François Alcover at Fri Jun 14 07:07:17 EDT 2013

STATUS

editing

proposed

#11 by Jean-François Alcover at Fri Jun 14 07:07:11 EDT 2013

MATHEMATICA

(* Assuming mod(a(n), 24) = 2 *) Reap[ For[ k = 2, k <= 2 + 240000, k = k + 24, pr = Select[ PowersRepresentations[k, 2, 2], PrimeQ[#[[1]]] && PrimeQ[#[[2]]] &]; If[Length[pr] == 4 , Print[k]; Sow[k]]]][[2, 1]] (* Jean-François Alcover, Jun 14 2013 *)

STATUS

proposed

editing

#10 by Zak Seidov at Fri Jun 14 04:32:41 EDT 2013

STATUS

editing

proposed

#9 by Zak Seidov at Fri Jun 14 04:32:25 EDT 2013

COMMENTS

Suggestion: All first differences are divisible by 24. - Zak Seidov, Jun 14 2013

STATUS

approved

editing

#8 by T. D. Noe at Thu Jun 13 14:40:14 EDT 2013

STATUS

editing

approved