b21 := (1,3,6,11,17)(2,4,8,14,21)(5,9,15,23,34)(7,12,18,28,41)(10,16,25,37,54)
     (13,19,30,44,63)(20,31,45,65,93)(22,33,48,70,43)(24,35,51,73,105)(26,38,
     56,80,113)(27,39,58,83,118)(29,42,61,88,126)(32,46,67,96,136)(36,52,75,
     108,148)(40,59,85,121,165)(47,68,98,139,101)(49,71,102,141,143)(53,76,
     109,149,197)(55,78,60,86,123)(57,81,115,157,206)(62,89,82,116,159)(64,91,
     129,175,100)(66,94,133,180,236)(69,99,140,187,245)(72,103,107,146,193)
     (74,106,145,191,114)(77,110,151,199,155)(79,112,154,204,164)(84,119,162,
     213,271)(87,124,168,218,267)(90,127,172,224,122)(92,130,177,231,285)(95,
     134,182,239,295)(97,137,185,242,298)(111,152,201,258,314)(117,160,210,
     268,323)(120,163,214,272,329)(125,169,220,241,297)(128,173,226,281,334)
     (131,178,233,288,342)(132,179,234,290,138)(135,183,166,215,273)(142,189,
     247,223,279)(144,190,249,305,360)(147,194,238,293,322)(150,198,256,212,
     270)(153,202,260,316,367)(156,205,263,244,300)(158,207,265,320,365)(161,
     211,269,325,308)(167,216,228,250,306)(170,221,277,328,302)(171,222,278,
     332,326)(174,227,283,337,382)(176,229,284,338,362)(181,237,292,346,209)
     (184,240,296,350,389)(186,243,299,353,391)(188,246,252,192,251)(195,230,
     235,287,200)(196,253,309,363,392)(203,261,276,331,378)(208,266,321,374,
     254)(217,275,313,294,348)(225,262,317,369,356)(232,286,341,327,376)(248,
     303,357,394,370)(255,310,280,304,358)(257,312,366,351,390)(259,315,347,
     388,274)(264,318,371,400,354)(282,335,380,368,289)(291,344,385,311,364)
     (301,355,393,407,411)(307,361,397,409,359)(319,372,398,375,349)(324,339,
     383,404,412)(330,352,373,387,406)(333,377,402,336,381)(343,379,345,386,
     403)(395,408,401,410,414)(399,405,413,415,416);