1,2

Yields the row of A145605 in which n appears, and also the first row of A138180 in which n appears.

Table of n, a(n) for n=1..77.

a(n) = pi(A074399(n)), where pi = A000720.

(PARI) a(n)=primepi(vecmax(factor(n*(n+1))[, 1]))

Cf. A002071, A145604, A138180, A145605, A002072, A074399.

Sequence in context: A084054 A106747 A083447 * A332250 A059998 A234475

Adjacent sequences: A252486 A252487 A252488 * A252490 A252491 A252492

nonn

M. F. Hasler, Jan 16 2015

approved