OEIS 1, 5, 11, 19, 29, 41, https://oeis.org/search?q=1%2C+5%2C+11%2C+19%2C+29%2C+41%2C&language=japanese&go=%E6%A4%9C%E7%B4%A2 (n-1) + ((n-1)+1)^2 https://www.wolframalpha.com/input?i=%28n-1%29+%2B+%28%28n-1%29%2B1%29%5E2&lang=ja
OEIS
1, 5, 11, 19, 29, 41,
https://oeis.org/search?q=1%2C+5%2C+11%2C+19%2C+29%2C+41%2C&language=japanese&go=%E6%A4%9C%E7%B4%A2
(n-1) + ((n-1)+1)^2
https://www.wolframalpha.com/input?i=%28n-1%29+%2B+%28%28n-1%29%2B1%29%5E2&lang=ja