A104025 Least number k that can be written as k^2 * j with 0 < j <= k and gcd(k, j) = 1 in n ways.

2, 1, 100, 900, 44100, 108900, 1232100, 11492100, 5336100, 12744900, 97416900

Offset

0,1

Links

Table of n, a(n) for n=0..10.

Mathematica

t = Sort[ Flatten[ Table[n = k^2*j; If[ GCD[k, j] == 1 && 10^5 < n < 10^8, n, {}], {k, 15000}, {j, k}]]]; l = Length[t]; t[[Select[ Range[l - 11], t[[ # ]] == t[[ # + 9]] &]]]

Crossrefs

Cf. A102354, A104021, A104023.

Sequence in context: A141527 A301631 A191298 * A335600 A039923 A081708

Adjacent sequences: A104022 A104023 A104024 * A104026 A104027 A104028

Keyword

nonn

Author

Leroy Quet and Robert G. Wilson v, Feb 23 2005

Status

approved