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.

Showing 1-3 of 3 results.

A330686 Primorial deflation of (nonzero) K-champion numbers: a(n) is the unique integer x such that A108951(x) = A307866(1+n).

Original entry on oeis.org

1, 4, 3, 8, 6, 12, 9, 24, 18, 48, 20, 36, 96, 40, 72, 30, 54, 80, 144, 60, 108, 160, 288, 120, 216, 320, 90, 576, 240, 432, 180, 480, 864, 360, 960, 720, 1920, 540, 252, 1440, 3840, 1080, 504, 2880, 1200, 2160, 1008, 5760, 2688, 2400, 4320, 2016, 11520, 3240, 4800, 1512, 8640, 4032, 23040, 1680, 6480, 9600, 3024, 17280, 8064, 7200
Offset: 1

Views

Author

Antti Karttunen, Dec 28 2019

Keywords

Links

Crossrefs

Cf. A074206, A181815, A307866, A329900, A353568.

Formula

a(n) = A329900(A307866(1+n)).
a(n) = A122111(A353568(n)). - Antti Karttunen, May 20 2022

A353561 Prime shadows of colossally abundant numbers, A004490.

Original entry on oeis.org

2, 4, 6, 12, 20, 30, 60, 84, 168, 336, 528, 880, 1320, 2640, 5280, 10560, 12480, 24960, 49920, 74880, 104832, 209664, 419328, 838656, 1096704, 2193408, 4386816, 8773632, 14622720, 29245440, 58490880, 116981760, 233963520, 350945280, 701890560, 784465920, 1568931840, 2465464320, 4930928640, 9861857280, 14792785920
Offset: 1

Views

Author

Antti Karttunen, Apr 29 2022

Keywords

Comments

Sequence is injective (no duplicate values occur) because A004490 is a subsequence of A025487.

Links

Crossrefs

Cf. A004490, A025487, A122111, A181819, A342012.
Cf. also A353562, A353568.

Programs

  • PARI
    v004490 = readvec("b004490_to.txt"); \\ Prepared from b-file of A004490 with gawk ' { print $2 } '
A004490(n) = v004490[n];
A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));
A353561(n) = A181819(A004490(n));

Formula

a(n) = A181819(A004490(n)).
a(n) = A122111(A342012(n)).

A353562 Prime shadows of highly composite numbers, A002182.

Original entry on oeis.org

1, 2, 3, 4, 6, 10, 9, 14, 12, 20, 18, 28, 30, 42, 40, 36, 56, 60, 84, 100, 132, 140, 156, 126, 120, 196, 198, 168, 200, 264, 280, 312, 252, 440, 392, 396, 520, 336, 400, 528, 560, 624, 504, 880, 784, 792, 1040, 840, 936, 1360, 1320, 1176, 1120, 1560, 1008, 1760, 1568, 1584, 2080, 1680, 1872, 2720, 2640, 2352, 2240, 3120
Offset: 1

Views

Author

Antti Karttunen, Apr 29 2022

Keywords

Comments

Sequence is injective (no duplicate values occur) because A002182 is a subsequence of A025487.

Links

Crossrefs

Cf. A002182, A025487, A122111, A181819, A329902.
Cf. also A353561, A353568.

Programs

  • PARI
    v002182 = readvec("b002182_to.txt"); \\ Prepared from b-file of A002182 with gawk ' { print $2 } '
A002182(n) = v002182[n];
A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));
A353562(n) = A181819(A002182(n));

Formula

a(n) = A181819(A002182(n)).
a(n) = A122111(A329902(n)).
Showing 1-3 of 3 results.

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

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