A228378 Numbers n such that tb(n) = tb(n+1) where tb(n) = A048784(n) is the number of divisors of binomial(2*n, n).

9, 10, 22, 34, 44, 45, 51, 56, 82, 106, 130, 141, 142, 162, 166, 177, 185, 190, 230, 262, 273, 274, 320, 322, 346, 352, 354, 394, 440, 454, 470, 526, 536, 550, 562, 586, 606, 624, 635, 670, 692, 717, 754, 766, 779, 814, 826, 831, 862, 882, 891, 920, 934

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..2611

Mathematica

SequencePosition[Table[DivisorSigma[0, Binomial[2n, n]], {n, 1000}], {x_, x_}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 15 2019 *)

Prog

(PARI) lista(nn) = my(last = 0); for (i=1, nn, new = numdiv(binomial(2*i, i)); if (last == new, print1(i, ", ")); last = new) \\ Michel Marcus, Aug 21 2013

Crossrefs

Cf. A000005, A000984.

Sequence in context: A326523 A061410 A309485 * A326464 A174042 A263261

Adjacent sequences: A228375 A228376 A228377 * A228379 A228380 A228381

Keyword

nonn

Author

Michel Marcus, Aug 21 2013

Status

approved