A364659 -id:A364659 - cp's OEIS frontend

A364657 Numbers k such that sigma(k) > sigma(k+1) > sigma(k+2).

44, 45, 104, 105, 116, 117, 164, 165, 224, 225, 272, 273, 296, 297, 315, 344, 345, 356, 357, 405, 464, 465, 512, 513, 525, 560, 561, 584, 585, 620, 621, 693, 704, 705, 765, 776, 777, 824, 825, 836, 837, 860, 861, 884, 885, 945, 1004, 1005, 1112, 1113, 1125, 1155

Offset: 1

Seiichi Manyama, Aug 01 2023

Seiichi Manyama, Table of n, a(n) for n = 1..10000

Cf. A050944, A053226, A364659.

isok(n) = sigma(n)>sigma(n+1) && sigma(n+1)>sigma(n+2);

A364662 Numbers k such that sigma(k) < sigma(k+1) < sigma(k+2) < sigma(k+3).

Original entry on oeis.org

1, 61, 73, 133, 145, 193, 253, 397, 457, 481, 493, 553, 565, 613, 625, 661, 673, 733, 757, 793, 817, 853, 913, 973, 997, 1033, 1093, 1213, 1237, 1285, 1321, 1453, 1513, 1537, 1645, 1657, 1681, 1813, 1825, 1873, 1933, 2077, 2113, 2173, 2233, 2245, 2293, 2413, 2497, 2533, 2581, 2593, 2653, 2713

Offset: 1

Seiichi Manyama, Aug 01 2023

Seiichi Manyama, Table of n, a(n) for n = 1..10000

Cf. A050944, A053224, A364659.

PARI
```
isok(n) = sigma(n)
				
```

A364715 Numbers k such that d(k) < d(k+1) < d(k+2), where d(n) is the number of divisors of n.

Original entry on oeis.org

61, 62, 73, 163, 187, 193, 194, 206, 254, 274, 277, 278, 283, 313, 355, 361, 362, 397, 398, 403, 421, 422, 427, 454, 457, 458, 482, 493, 523, 538, 583, 613, 614, 661, 673, 691, 733, 746, 757, 758, 763, 823, 853, 866, 889, 926, 934, 943, 955, 997, 998, 1003, 1027

Offset: 1

Seiichi Manyama, Aug 04 2023

Cf. A000005, A075028, A364659, A364718.

Cf. A074775, A364716, A364717.

PARI
```
isok(n) = numdiv(n)
				
```

A364704 Smallest initial number k of n consecutive numbers satisfying sigma(k) < sigma(k+1) < ... < sigma(k+n-1).

Original entry on oeis.org

1, 1, 1, 1, 36721681, 36721681

Offset: 1

Seiichi Manyama, Aug 03 2023

a(7) > 5*10^10. (Calculated using the b-file in A028965.)

Cf. A000203, A075028, A285893, A364680.

Cf. A028965, A053224, A364659, A364662.

PARI
```
b(n) = my(k=n); while(sigma(k)
				
```

cp's OEIS Frontend

A364657 Numbers k such that sigma(k) > sigma(k+1) > sigma(k+2).

Views

Author

Keywords

Links

Crossrefs

Programs

PARI

A364662 Numbers k such that sigma(k) < sigma(k+1) < sigma(k+2) < sigma(k+3).

Views

Author

Keywords

Links

Crossrefs

Programs

PARI

A364715 Numbers k such that d(k) < d(k+1) < d(k+2), where d(n) is the number of divisors of n.

Views

Author

Keywords

Crossrefs

Programs

PARI

A364704 Smallest initial number k of n consecutive numbers satisfying sigma(k) < sigma(k+1) < ... < sigma(k+n-1).

Views

Author

Keywords

Comments

Crossrefs

Programs

PARI