cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A274565 Numbers k such that sigma(k) == 0 (mod k+10).

Original entry on oeis.org

14, 176, 1376, 3230, 3770, 6848, 114256, 125696, 544310, 561824, 740870, 2075648, 4199030, 4607296, 8436950, 33468416, 134045696, 199272950, 624032630, 1113445430, 1550860550, 85905593344, 2199001235456, 35184284008448
Offset: 1

Views

Author

Paolo P. Lava, Jul 06 2016

Keywords

Examples

			sigma(14) mod (14 + 10) = 24 mod 24 = 0.

Crossrefs

Contains subsequence A223611.
Contains 2 * odd terms of A223609.
Cf. A045770, A067702, A088833, A181598, A274551, A274552, A274553, A274554, A274556, A274557, A274558, A274559, A274560, A274561, A274562, A274563, A274564, A274566.

Programs

  • Magma
    [n: n in [1..2*10^6] | SumOfDivisors(n) mod (n+10) eq 0 ]; // Vincenzo Librandi, Jul 06 2016
  • Mathematica
    k = 10; Select[Range[Abs@k+1, 10^6], Mod[DivisorSigma[1, #], # + k] == 0 &] (* Vincenzo Librandi, Jul 06 2016 *)

Extensions

a(13)-a(23) from Giovanni Resta, Jul 06 2016
a(24) from Max Alekseyev, May 29 2025

A181601 Numbers m with divisor 32 | m and abundance sigma(m)-2*m = 32.

Original entry on oeis.org

992, 28544, 122624, 507392, 537248, 698528, 791264, 1081568, 1279136, 2279072, 5029184, 307801856, 623799776, 712023296, 11196261056, 14809750016, 34355412992, 59640734144, 340536203264, 637707589184, 1091487733184, 1473169206272, 1709840369984, 2526522709184
Offset: 1

Views

Author

Vladimir Shevelev, Nov 01 2010

Keywords

Comments

A subsequence of A175989. - R. J. Mathar, Nov 04 2010

Links

Crossrefs

Cf. A000203, A005101, A005820, A045768, A097498, A118372, A153501, A175989, A181595, A181596, A181597, A181598, A181599.

Programs

  • Mathematica
    Select[32Range[1000000],DivisorSigma[1,#]-2#==32&] (* Harvey P. Dale, Aug 16 2011 *)

Extensions

Definition rephrased, a(5)-a(11) appended - R. J. Mathar, Nov 04 2010
a(12)-a(24) from Donovan Johnson, Dec 08 2011

A181599 Numbers m with divisor 16 | m and abundance sigma(m)-2*m = 16.

Original entry on oeis.org

1504, 30592, 4526272, 8353792, 361702144, 1081850752, 1845991216, 2146926592, 21818579968, 34357510144, 228354264064, 549746900992, 2169800814592, 8796057370624, 24038405705152, 80952364306432, 140737345748992, 2737658648639872, 23810602502029312, 36979953305070592
Offset: 1

Views

Author

Vladimir Shevelev, Nov 01 2010

Keywords

Crossrefs

Cf. A097498, A141547, A181595, A181596, A181597, A181598, A118372, A045768, A000396, A005101, A153501, A005820.

Formula

A008598 INTERSECT A141547. - R. J. Mathar, Nov 04 2010

Extensions

Definition rephrased - R. J. Mathar, Nov 04 2010
a(9)-a(13) from Donovan Johnson, Dec 08 2011
a(14)-a(20) from the b-file at A141547 added by Amiram Eldar, Aug 03 2024
Previous Showing 11-13 of 13 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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