For the regular sequence 1, 2, 3, ..., \(n\), then sum is
\(\frac{n(n+1)}{2}\)
If we multiply each number by 7 (7, 14, 21, ...), then the sum is
\(\frac{7n(n+1)}{2}\)
and if we add 1 to each number (8, 15, 22, ...) then the sum is
\(\frac{7n(n+1)}{2}+n\)
We have \(n=26\) terms, so the sum is:
\(\frac{7(26)(27)}{2}+26\)
\(=7(13)(27)+26\)
\(=91(27)+26\)
\(=2457+26\)
\(=2483\)
