login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A089221
a(n) = floor(sqrt(((prime(n) + primepi(n))/2)^2 + prime(n)*primepi(n))).
0
1, 2, 4, 5, 9, 10, 13, 14, 16, 19, 21, 25, 28, 29, 31, 34, 38, 39, 44, 46, 47, 50, 53, 56, 60, 62, 63, 65, 68, 70, 78, 80, 83, 84, 89, 90, 94, 98, 100, 103, 107, 108, 114, 115, 117, 118, 126, 132, 134, 135, 137, 140, 142, 147, 150, 153, 156, 157, 162, 164, 166, 171, 178
OFFSET
1,2
MATHEMATICA
f[n_]=Floor[Sqrt[((Prime[n]+PrimePi[n])/2)^2+Prime[n]*PrimePi[n]]]
a=Table[f[n], {n, 1, 200}]
CROSSREFS
Sequence in context: A289175 A274693 A024618 * A347877 A167180 A091271
KEYWORD
nonn,less
AUTHOR
Roger L. Bagula, Jan 03 2004
STATUS
approved