A075033 -id:A075033 - cp's OEIS frontend

A075032 Numbers n such that tau(n) <= tau(n+1) <= tau(n+2) where tau(n) = number of divisors of n.

1, 2, 13, 14, 25, 26, 33, 34, 37, 38, 43, 61, 62, 73, 74, 85, 86, 93, 94, 97, 98, 103, 115, 118, 121, 122, 133, 134, 141, 142, 145, 146, 157, 158, 163, 187, 188, 193, 194, 201, 202, 205, 206, 213, 214, 217, 218, 229, 230, 241, 242, 243, 244, 253, 254, 274, 277

Offset: 1

Amarnath Murthy, Sep 02 2002

nonn

Karl V. Keller, Jr., Table of n, a(n) for n = 1..10000

Cf. A000005, A075033, A075034, A075035, A005238 (subsequence).

from sympy import divisor_count as tau
[n for n in range(1,303) if tau(n) <= tau(n+1) <= tau(n+2)] # Karl V. Keller, Jr., Jul 10 2020

Corrected and extended by Benoit Cloitre, Sep 07 2002

A075034 Numbers n such that tau(n) >= tau(n+1) >= tau(n+2) where tau(n) = number of divisors of n.

Original entry on oeis.org

20, 21, 32, 33, 44, 45, 56, 57, 75, 80, 81, 84, 85, 92, 93, 104, 105, 116, 117, 132, 135, 140, 141, 144, 147, 165, 170, 171, 176, 177, 189, 200, 201, 204, 212, 213, 216, 217, 224, 225, 230, 231, 242, 243, 252, 260, 261, 272, 285, 296, 297, 300, 301, 315, 324

Offset: 1

Amarnath Murthy, Sep 02 2002

nonn

Karl V. Keller, Jr., Table of n, a(n) for n = 1..10000

Cf. A000005 (tau), A075032, A075033, A075035.

nn = 400; t = DivisorSigma[0, Range[nn]]; Select[Range[nn-2], t[[#]] >= t[[#+1]] >= t[[#+2]] &] (* Harvey P. Dale, May 24 2012 *)

from sympy import divisor_count as tau
[n for n in range(1,333) if tau(n) >= tau(n+1) >= tau(n+2)] # Karl V. Keller, Jr., Jul 10 2020

More terms from Benoit Cloitre, Sep 07 2002

A075035 Numbers n such that tau(n) >= tau(n+1) >= tau(n+2) >= tau(n+3) where tau(n) = number of divisors of n.

Original entry on oeis.org

20, 32, 44, 56, 80, 84, 92, 104, 116, 140, 170, 176, 200, 212, 216, 224, 230, 242, 260, 296, 300, 324, 332, 344, 374, 380, 392, 434, 440, 444, 464, 476, 500, 506, 512, 560, 594, 602, 608, 620, 632, 644, 650, 696, 704, 714, 715, 716, 740, 776, 800, 804, 836

Offset: 1

Amarnath Murthy, Sep 02 2002

nonn

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Cf. A075032, A075033, A075034.

Position[Partition[DivisorSigma[0,Range[900]],4,1],?(Max[ Differences[ #]]< 1&),1,Heads->False]//Flatten (* _Harvey P. Dale, Sep 05 2019 *)

from sympy import divisor_count as tau
[n for n in range(1,901) if tau(n) >= tau(n+1) >= tau(n+2) >= tau(n+3)] # Karl V. Keller, Jr., Jul 10 2020

More terms from Benoit Cloitre, Sep 07 2002

cp's OEIS Frontend

A075032 Numbers n such that tau(n) <= tau(n+1) <= tau(n+2) where tau(n) = number of divisors of n.

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A075034 Numbers n such that tau(n) >= tau(n+1) >= tau(n+2) where tau(n) = number of divisors of n.

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A075035 Numbers n such that tau(n) >= tau(n+1) >= tau(n+2) >= tau(n+3) where tau(n) = number of divisors of n.

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