A375195 - OEIS

A375195

Numbers k such that A025487(k) and A025487(k+1) have an equal number of divisors.

4, 8, 15, 22, 69, 116, 122, 134, 135, 168, 208, 278, 400, 453, 538, 584, 718, 1019, 1409, 1671, 1799, 2035, 2417, 2541, 2595, 2783, 3424, 3809, 3860, 4415, 5628, 6267, 6672, 6745, 6872, 6873, 7277, 9436, 9845, 10182, 10191, 10936, 11272, 11472, 12105, 16139, 16277

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Numbers k such that A146288(k) = A146288(k+1).

The corresponding values of A146288(k) are 4, 8, 12, 16, 48, 48, 96, 80, 80, ... .

The corresponding values of A025487(k) are 6, 24, 72, 210, 5400, ... (A375196).

Numbers k such that A146288(k) = A146288(k+1) = A146288(k+2) are 134, 6872, 6699401, 12421946, ... .

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..4390

FORMULA

A025487(a(n)) = A375196(n).

EXAMPLE

4 is a term since A146288(4) = A146288(5) = 4.

MATHEMATICA

With[{lps = Cases[Import["https://oeis.org/A025487/b025487.txt", "Table"], {_, _}][[;; , 2]]}, Position[Differences[DivisorSigma[0, lps]], 0] // Flatten]

CROSSREFS

Cf. A000005, A025487, A146288, A375196.

Sequence in context: A102216 A001182 A264599 * A122247 A126255 A267682

Adjacent sequences: A375192 A375193 A375194 * A375196 A375197 A375198

KEYWORD

nonn

AUTHOR

Amiram Eldar, Aug 04 2024

STATUS

approved