A173149 Numbers n such that max(tau(n),tau(n+1),tau(n+2))- min(tau(n),tau(n+1),tau(n+2)) = 1.

1, 2, 3, 8, 14, 25, 121, 841, 1442, 6241, 8281, 16641, 20164, 24962, 26894, 28561, 46225, 55225, 58564, 65534, 67081, 73441, 93025, 104329, 110888, 116281, 143641, 149768, 155236, 212521, 235225, 252003, 271441, 279841, 284089, 293762, 293763

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Example

For n = 1, max(tau(1),tau(2),tau(3)) - min(tau(1),tau(2),tau(3)) = max(1,2,2) - min(1,2,2) = 1.
For n = 121, max(tau(121),tau(122),tau(123)) - min(tau(121),tau(122),tau(123)) = max(1,2,2) - min(1,2,2) = 1

Maple

with(numtheory):for n from 1 to 1500000 do; if max(tau(n), tau(n+1), tau(n+2))- min(tau(n), tau(n+1), tau(n+2))= 1 then print(n); else fi ; od;

Mathematica

Select[Range[10^6], Max[(d = DivisorSigma[0, #+{0, 1, 2}])] - Min[d] == 1 &] (* Amiram Eldar, Aug 14 2019 *)

Crossrefs

Sequence in context: A022951 A247124 A171237 * A128305 A328881 A298349

Adjacent sequences: A173146 A173147 A173148 * A173150 A173151 A173152

Keyword

nonn

Author

Michel Lagneau, Feb 11 2010, Feb 13 2010

Status

approved