A274357 Numbers n such that n and n+1 both have 8 divisors.

104, 135, 189, 230, 231, 285, 296, 344, 374, 375, 429, 434, 609, 645, 663, 664, 741, 776, 782, 805, 874, 902, 903, 969, 986, 1001, 1015, 1022, 1029, 1065, 1085, 1095, 1105, 1106, 1112, 1130, 1161, 1208, 1221, 1245, 1265, 1269, 1309, 1310, 1334, 1335, 1374, 1406, 1431

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Mathematica

SequencePosition[DivisorSigma[0, Range[2000]], {8, 8}][[All, 1]] (* Harvey P. Dale, Sep 07 2021 *)

Prog

(PARI) is(n)=numdiv(n)==8 && numdiv(n+1)==8

Crossrefs

Intersection of A005237 and A030626.

Numbers n such that n and n+1 both have k divisors: A039832 (k=4), A049103 (k=6), A274357 (k=8), A215197 (k=10), A174456 (k=12), A274358 (k=14), A274359 (k=16), A274360 (k=18), A274361 (k=20), A274366 (k=22), A274362 (k=24), A274363 (k=26), A274364 (k=28), A274365 (k=30).

Cf. A000005.

Sequence in context: A306291 A055036 A358396 * A052476 A297912 A253700

Adjacent sequences: A274354 A274355 A274356 * A274358 A274359 A274360

Keyword

nonn

Author

Charles R Greathouse IV, Jun 19 2016

Status

approved