A073173 Square composite numbers with square subscripts.

4, 9, 16, 1225, 6036849, 10909809, 29484900, 326561041, 653058025, 952833424, 10487398464

Offset

1,1

Comments

a(12) > 5*10^11. [From Donovan Johnson, Feb 06 2010]

Links

Table of n, a(n) for n=1..11.

Formula

Solutions to c[x^2]=y^2: the values of y^2; where c(j)=j-th composite number; See program.

Example

composite=1225=35.35=A002808(1024)=c(32.32).

Mathematica

c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] Do[s=c[n^2]; If[IntegerQ[Sqrt[s]], Print[s]], {n, 1, 1000000}]

Crossrefs

Cf. A002808, A073171, A073172.

Sequence in context: A082920 A204434 A110979 * A313352 A253601 A313353

Adjacent sequences: A073170 A073171 A073172 * A073174 A073175 A073176

Keyword

nonn

Author

Labos Elemer, Jul 19 2002

Extensions

a(10)-a(11) from Donovan Johnson, Feb 06 2010

Status

approved