2,2

From David W. Wilson, Jan 08 2017: (Start)

a(n)^2 = A076956(n).

A014085(a(n)) = n.

Conjecturally, a(n) is undefined for n = 1 and defined for all n >= 2. (End)

T. D. Noe and David W. Wilson, Table of n, a(n) for n = 2..10000 (a(n) for n = 2..1000 from T. D. Noe).

a := proc(n) local k, h, SEARCHLIMIT; SEARCHLIMIT := 10000; h := proc(k) option remember; nops(select(j->isprime(j), [$k^2+1..(k+1)^2])) end: k := 1; while h(k) <> n and k < SEARCHLIMIT do k := k+1 od; `if`(k=SEARCHLIMIT, print("Search limit reached!"), k) end: seq(a(n), n=2..56); # Peter Luschny, Jan 10 2017

Table[k = 1; While[Count[Map[PrimeQ, Range[k^2 + 1, (k + 1)^2]], True] != n, k++]; k, {n, 2, 56}] (* Michael De Vlieger, Jan 10 2017 *)

With[{pp=Table[Count[Range[n^2+1, (n+1)^2-1], _?(PrimeQ[#]&)], {n, 500}]}, Table[ Position[pp, k, 1, 1], {k, 60}]]//Flatten (* Harvey P. Dale, Aug 01 2021 *)

Cf. A014085, A076956, A084597.

Sequence in context: A388971 A140611 A333846 * A310585 A179445 A310586

Adjacent sequences: A076954 A076955 A076956 * A076958 A076959 A076960

Amarnath Murthy, Oct 20 2002

More terms from Ralf Stephan, Oct 31 2002

approved