5、12、21、32、45、60······求第n个数是什么

5、12、21、32、45、60······求第n个数是什么 1+2+3+4+5+6+7+8+9+1+11+12+13+14+15````````1+2+3+4+5+6+7+8+9+1+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28++29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50·································· 把这些数字由基数词变成序数词1·2·3·4·5·6·7·8·9·10·11·12·20·30·40·50·60·70·80·90·21·35·78 22-12=3,32-22=5·······用n表示其规律 1 2 9 10 25 26 ··· 4 3 8 11 24 27 ··· 5 6 7 12 23 26··· 17 1816 15 14 13 22 29···1 2 9 10 25 26 ··· 4 3 8 11 24 27 ··· 5 6 7 12 23 26···16 15 14 13 22 29·· ·17 18 19 20 21 30···36 35 34 33 32 31··· · 变态数学题·······方程一道············x+2y+3z=1x=y+12x+3y+5z=2方程组············要过程············我解了之后总觉得无解····· 从光谱数据9/5,16/12,25/21,36/32,········请你按照这种规律,写出第n(n≥1)个数据是（ ） 找规律的应用题有19个等式,如下表：1+2+3=4+5-36+7+8+9=10+11+12-313+14+15+16+17=18+19+20+21-322+23+24+25+26+27=28+29+30+31+32-334+35+36+37+38+39=40+41+42+43+44+45-3············那么,第19个等式左右两边的结果是多 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? 人教版小学六年级数学上册12到13页的2,5,6,快············· 数学题（16x-13)/(4x-3)+（40x-43)/(8x-9)=（32x-30)/(8x-7)+（20x-24)/(4x-5)在线等··············求过程··············· 32·········· 序列 1 2 3 4 5 6 ······ n 对应的数 1 3 6 10 21······? 小数口算题,15道,比如5.8*5,2.5*4,6.5/0.5.写清楚点,格式：····························································· 段字加偏旁再组词、、、、、、、、、、、、5分钟内,快···················· 32%x+45%x=1.3方程·····快 破釜沉舟的故事·······简单点····60字················急 找规律:1·5·11·10·21·15·31·()·()急