高校数学の質問スレPart399

Table[2n-1+{(n-4)+3mod4}+C(1,n-9)((-1)^n+1)/2+C(3,n-8)((-1)^(n+1)+1)/2,{n,1,10}]

{1, 4, 7, 10, 9, 12, 15, 18, 20, 21}

☆☆☆