A254035 Sequence A255412 sorted into ascending order, with duplicates removed.

4800, 28800, 57600, 67200, 86400, 96000, 115200, 142800, 144000, 148800, 153600, 182400, 201600, 211200, 230400, 259200, 288000, 297600, 326400, 345600, 355200, 384000, 403200, 432000, 470400, 489600, 499200, 518400, 528000, 547200, 576000, 614400, 633600, 638400, 662400, 672000, 691200, 720000, 729600

Offset: 1

Author

Naohiro Nomoto, Jan 23 2015

Keywords

• nonn

Comments

Numbers n such that n = A000203(j) = A000203(k) and A007947(j) = A007947(k), where j != k.

In other words, numbers n such that sigma(x) = n has at least two distinct solutions, with each x having the same squarefree kernel, where sigma(x) is the sum of divisor function (A000203).

Equally, sequence A000203(A255335(n)) sorted into ascending order, with duplicates removed.

Examples

			4800 is the sum of divisors of 1512 and 2058, and rad(1512) = rad(2058) = 42, hence 4800 is in the sequence with j=1512 and k=2058.
		

Crossrefs

Subsequence of A159886.

Cf. A000203 (sum of divisors of n), A007947 (squarefree kernel of n).

Cf. A254791 (a subsequence).

Cf. A252997, A255334, A255335, A255412.

Formula

a(n) = A000203(A255334(n)) = A000203(A255335(n)) for n = 1 .. 7. - Antti Karttunen, Apr 05 2015

Extensions

More terms from Antti Karttunen, Apr 13 2015