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Revision History for A121085 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Number of primitive Pythagorean-like triples a^2+b^2=c^2+k for k=-3 with 0<c<=10^n.
(history; published version)
#12 by Joerg Arndt at Sat Oct 17 09:22:51 EDT 2015
STATUS

proposed

approved

#11 by Michel Marcus at Sat Oct 17 09:22:44 EDT 2015
STATUS

editing

proposed

#10 by Michel Marcus at Sat Oct 17 09:22:35 EDT 2015
MATHEMATICA

Courtesy of Daniel Lichtblau of Wolfram Research: countTriples[m_, k_] := Module[ {c2, c2odd, total = 0, fax, g}, Do[ c2 = c^2 + k; If[c2 < 2, Continue[]]; c2odd = c2; While[EvenQ[c2odd], c2odd /= 2]; If [c2odd==1, If [OddQ[Log[2, c2]], total++ ]; Continue[]]; If[Mod[c2odd, 4] == 3, Continue[]]; g = GCD[c2odd, 100947]; If[g != 1 && g^2 != GCD[c2odd, 10190296809], Continue[]]; fax = Map[{Mod[ #[[1]], 4], #[[2]]}&, FactorInteger[c2odd]]; If[Apply[Or, Map[ #[[1]] == 3 && OddQ[ #[[2]]] &, fax]], Continue []]; fax = Cases[fax, {1, aa_}:>aa+1]; fax = Ceiling[Apply[Times, fax]/2]; total += fax; , {c, m}]; total] (* Courtesy of Daniel Lichtblau of Wolfram Research *)

STATUS

approved

editing

#9 by Joerg Arndt at Sat Oct 17 09:22:04 EDT 2015
STATUS

proposed

approved

#8 by Hiroaki Yamanouchi at Sat Oct 17 09:10:27 EDT 2015
STATUS

editing

proposed

#7 by Hiroaki Yamanouchi at Sat Oct 17 09:10:22 EDT 2015
DATA

3, 30, 293, 2881, 28871, 288685, 2886366, 28868362, 288673693, 2886752763

EXTENSIONS

a(8)-a(10) from Hiroaki Yamanouchi, Oct 17 2015

STATUS

approved

editing

#6 by Russ Cox at Sat Mar 31 10:31:08 EDT 2012
AUTHOR

_Tito Piezas III (tpiezas(AT)gmail.com), _, Aug 11 2006

EXTENSIONS

First few terms found by _Tito Piezas III (tpiezas(AT)gmail.com), _, James Waldby (j-waldby(AT)pat7.com). Subsequent terms found by Andrzej Kozlowski (akoz(AT)mimuw.edu.pl), Daniel Lichtblau (danl(AT)wolfram.com).

Discussion
Sat Mar 31
10:31
OEIS Server: https://oeis.org/edit/global/694
#5 by Russ Cox at Fri Mar 30 17:26:55 EDT 2012
EXTENSIONS

a(7) from _Max Alekseyev (maxale(AT)gmail.com), _, Jul 03 2011

Discussion
Fri Mar 30
17:26
OEIS Server: https://oeis.org/edit/global/140
#4 by Max Alekseyev at Sun Jul 03 21:10:33 EDT 2011
STATUS

proposed

approved

#3 by Max Alekseyev at Sun Jul 03 21:10:22 EDT 2011
DATA

3, 30, 293, 2881, 28871, 288685, 2886366

COMMENTS

First few terms found by Tito Piezas III (tpiezas(AT)gmail.com), James Waldby (j-waldby(AT)pat7.com). Subsequent terms found by Andrzej Kozlowski (akoz(AT)mimuw.edu.pl), Daniel Lichtblau (danl(AT)wolfram.com). It is conjectured by the first author that a(n)/10^n as n->inf is 1/(2*sqrt(3)) = 0.28867...

EXTENSIONS

First few terms found by Tito Piezas III (tpiezas(AT)gmail.com), James Waldby (j-waldby(AT)pat7.com). Subsequent terms found by Andrzej Kozlowski (akoz(AT)mimuw.edu.pl), Daniel Lichtblau (danl(AT)wolfram.com).

a(7) from Max Alekseyev (maxale(AT)gmail.com), Jul 03 2011

STATUS

approved

proposed