Happy new year dear seq fans. Today I think I found a FORMULA FOR A283623:
a(n) = prime(n) + (1 + prime(1 + n))/2.
4, 6, 9, 13, 18, 22, 27, 31, 38, 45, 50, 58, 63, ...
EXAMPLE
a(1) = 2 + (1 + 3)/2 = 4,
a(2) = 3 + (1 + 5)/2 = 6,
a(3) = 5 + (1 + 7)/2 = 9.
METHOD
Using the constant A249270
Decimal expansion of lim_{n->oo} (1/n)*Sum_{k=1..n} smallest prime not dividing k: 2.9200509773161347120925629171120194680027278993214267...
The ceil integer parts of the sequence having this constant as starting value and thereafter x[n+1] = (frac(x[n])+1)*floor(p[n]) where p are the prime numbers >=3.
Example
ceil(3(2.9200509773161347120925629171120194680027278993214267-2+1)) = 6
What do you think?
Is this interesting?
Davide