A277893 A277893(n) = the least k > n for which A277892(k) = A277892(n), 0 if no such number exists.

0, 4, 6, 9, 8, 25, 10, 12, 18, 49, 14, 93, 15, 16, 20, 169, 22, 287, 21, 26, 24, 361, 30, 33, 27, 28, 34, 529, 32, 802, 40, 35, 36, 44, 38, 934, 39, 48, 42, 1333, 46, 1681, 45, 51, 54, 1754, 50, 58, 52, 55, 64, 2209, 56, 57, 66, 60, 65, 2809, 62, 2966, 63, 68, 74, 77, 70

Offset

2,2

Comments

a(n) is the least k larger than n for which the number of divisors of A048675(k) is equal to the number of divisors of A048675(n) (counted with multiplicity), and 0 if no such number exists (which happens only for n=2).

Links

Antti Karttunen, Table of n, a(n) for n = 2..102 (computed from the b-file provided by Hans Havermann for A277892)

Formula

For n >= 3, A277894(a(n)) = n.

Prog

(Scheme) (define (A277893 n) (cond ((= 2 n) 0) (else (let ((v (A277892 n))) (let loop ((k (+ 1 n))) (if (= (A277892 k) v) k (loop (+ 1 k))))))))

Crossrefs

Cf. A048675, A277892, A277894, A277898.

Sequence in context: A218036 A236536 A084335 * A197575 A201660 A341577

Adjacent sequences: A277890 A277891 A277892 * A277894 A277895 A277896

Keyword

nonn

Author

Antti Karttunen, Nov 08 2016

Status

approved