You need the rule that generates the sequence.
2n+4: 6,8,10......104........204
104
100000000000
1125899906842624
A number is a single term so there cannot be a 50th term for a number.
50th term means n = 50 So the term is 100-50 = 50
2
88
You need the rule that generates the sequence.
47
Nth term With the nth term you substitute the n for the term number (e.g. 50) so the 50th term in 2n+3 would be 2x50+3=103
The golden years are those surrounding the 50th (Golden) Anniversary.
You first have to figure out some rule for the sequence. This can be quite tricky.
I count five. - Polk, Cleveland, Teddy Roosevelt, Clinton and Obama. Garfield was 49 when he was killed and would have celebrated his 50th birthday in about 3 months. Kennedy would have become 50 in his second term, if he had had a second term.
List of triangular numbers 1,3,6,... work out the rest
it was the 50th state