A255412 a(n) = A000203(A255334(n)).

4800, 28800, 57600, 67200, 86400, 96000, 115200, 148800, 144000, 142800, 153600, 182400, 201600, 211200, 230400, 259200, 345600, 288000, 297600, 403200, 326400, 345600, 355200, 384000, 403200, 518400, 432000, 576000, 470400, 489600, 499200, 518400, 528000, 547200, 691200, 638400, 748800, 614400, 633600, 662400, 672000, 806400, 864000, 856800, 720000

Offset

1,1

Comments

Sequence gives value of sigma(n) for numbers n for which there exists k > n such that A000203(k) = A000203(n) and A007947(k) = A007947(n), where A000203 gives the sum of divisors, and A007947 gives the squarefree kernel of n. The sequence is ordered by the magnitude of n, and contains duplicates, because there are cases of multiple such pairs having the same value of sigma.

The first such duplicate values occur as a(17) = a(22) = 345600 and a(20) = a(25) = 403200.

Links

Antti Karttunen, Table of n, a(n) for n = 1..6589

Formula

a(n) = A000203(A255334(n)).

a(n) = A000203(A255423(n)).

Prog

(Scheme) (define (A255412 n) (A000203 (A255334 n)))

Crossrefs

Cf. A254035 (same sequence sorted into ascending order, with duplicates removed).

Cf. A000203, A007947, A255334, A255423, A255424.

Sequence in context: A221005 A227495 A254035 * A254791 A096790 A157516

Adjacent sequences: A255409 A255410 A255411 * A255413 A255414 A255415

Keyword

nonn

Author

Antti Karttunen, Apr 05 2015

Status

approved