Bruns constant and the Twin prime constant ========================================== Long double precision (80 bit). n = 1000000000000 = 1.000E+12; base (bytes) = 200000; n base eff. = 3200000 Start time: 2005-05-16 16:36:58 s CPU lm m Primes <= m Prime twins <= m Bruns constant B2 Twin prime const. ----------------------------------------------------------------------------------------------------------------------------------- 0.15 1 10 4 2 2.0637144501446804 0.8761904761904762 0.6835937500000000 0.15 2 100 25 8 1.9054552022712925 1.3309903657190868 0.6613770845471850 0.15 3 1000 168 35 1.9003539079684256 1.5180324635595910 0.6602457439708007 0.15 4 10000 1229 205 1.9036010057320106 1.6168935574322006 0.6601682965055034 0.16 5 100000 9592 1224 1.9021634758649511 1.6727995848277415 0.6601623454667365 0.18 6 1000000 78498 8169 1.9019133662823222 1.7107769308042211 0.6601618605898408 0.91 7 10000000 664579 58980 1.9021882641833462 1.7383570439172709 0.6601618197154555 7.99 8 100000000 5761455 440312 1.9021679380347306 1.7588156210679750 0.6601618161876178 76.51 9 1000000000 50847534 3424506 1.9021602393268651 1.7747359576385369 0.6601618158772920 756.55 10 10000000000 455052511 27412679 1.9021603562338200 1.7874785027192417 0.6601618158489871 -1022.04 11 100000000000 4118054813 224376048 1.9021605414229175 1.7979043109551190 0.6601618158489871 -1814.54 12 1000000000000 37607912018 1870585220 1.9021606304380325 1.8065924191758839 0.6601618158489871 -1814.53 ln 1000000000000 37607912018 1870585220 1.9021606304380325 1.8065924191758839 0.6601618158489871 ----------------------------------------------------------------------------------------------------------------------------------- Stop time: 2005-05-17 13:41:30 Elapsed clock time: 0.87814815 days = 21.075556 hours = 75872.00 seconds Comment by Stefan Spaennare 2005-05-17 ====================================== The program (cbrun3l.c) was run on a 1400 MHz Intel Celeron computer with 256 kbyte L2 cache (Advance Transfer) and 576 Mbyte primary memory. The memory bus was 100 MHz. Operating system was Fedora Core 3 Linux and compiler Intel icc C/C++ 8.1 with the following options: icc -O2 -tpp6 -xK -ip -long_double. The load was 1.00 (i.e. no other programs running). References ========== The web page "Mathematical Constants and Computation" by Xavier Gourdon and Pascal Sebah: http://numbers.computation.free.fr/Constants/constants.html