OFFSET
1,2
COMMENTS
It is conjectured that 772277 is the largest odd integer which cannot be expressed as p + q*(q-1) where p and q are primes.
q*(q-1) is even which implies that p must be an odd prime.
The expression p + q*(q-1) resembles the expression p + 2*q used in Lemoine's conjecture.
LINKS
Marc Ridders, Table of n, a(n) for n = 1..150
MATHEMATICA
a[1]=1; a[n_]:=a[n]=(k=a[n-1]; c=True; While[c, k=k+2; c=False; q=2; While[!c&&q*(q-1)<k, p=k-(q*(q-1)); c=PrimeQ[p]; q=NextPrime[q]]]; k); Table[a[n], {n, 1, 150}]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Marc Ridders, Feb 25 2023
STATUS
approved