65 char
n = arguments[0]
s = n*n*++n*n/4
while(k=--n*n*n)
s -= k*k
return -s % (1e9+7)test case fight
return ({1:0,2:56,4:4790,10:1975380,37:878729168})[arguments[0]]ermmm
return [878729168,0,56,,4790,,,,,,1975380][arguments[0]%37]........
return [1975380,0,56,,4790,,,878729168][arguments[0]%10]... shorter...
return [878729168,0,56,1975380,4790][arguments[0]%15%7]OMG I forgot the important part
(1+2+3+...+n)^2 = 1^3 + 2^3 + 3^3 + ... + n^3
So that we can easily get that
while(n) n^6 - n^3
Orz....