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.

A074055 Numbers k such that A074037(k) = A002034(k).

Original entry on oeis.org

350, 525, 700, 1050, 1400, 1575, 1792, 2100, 2800, 3150, 4200, 4725, 5376, 5600, 6300, 6655, 8400, 8960, 9450, 11200, 12600, 14175, 15379, 16128, 16800, 18900, 22400, 25200, 26880, 28350, 33275, 33600, 37800, 44800, 46585, 48384, 50400, 56700, 67200, 75600
Offset: 1

Views

Author

Jason Earls, Sep 15 2002

Keywords

Comments

Numbers k such that sum of composites between smallest prime factor of k and largest prime factor of k is the Kempner function A002034(k).

Examples

			A002034(350) = 10 and 350 = 2*5*5*7, so sum of composites between 2 and 7 = 4+6 = 10.

Links

Crossrefs

Cf. A002034, A074037.

Extensions

More terms from Paul Richards, Sep 20 2007
Missing terms inserted by Sean A. Irvine, Jan 07 2025

A074053 Numbers n such that A001414(n) = sum of composites from the smallest prime factor of n to the largest prime factor of n.

Original entry on oeis.org

1, 21, 5324, 9625, 12705, 13552, 15246, 18150, 19360, 21780, 22638, 23232, 26136, 26950, 29403, 32340, 34496, 38500, 38808, 39325, 41405, 43659, 46137, 46200, 49280, 51909, 51975, 55000, 55440, 59136, 61875, 62370, 65910, 66000, 66528
Offset: 1

Views

Author

Jason Earls, Sep 15 2002

Keywords

Examples

			Sum of primes dividing 5324 with repetition is: 2+2+11+11+11 = 37 and sum of composites between 2 and 11 is 4+6+8+9+10 = 37.

Crossrefs

Cf. A001414, A074037.

A076207 Triangular numbers whose sum of primes from smallest to largest prime factor is triangular and whose sum of composites from smallest to largest prime factor is triangular.

Original entry on oeis.org

3, 21, 105, 325, 7875, 9568125
Offset: 1

Views

Author

Jason Earls, Nov 02 2002

Keywords

Comments

No more terms < 2.77*10^12. - David Wasserman, Jul 20 2005
a(7) > 2*10^15. - Donovan Johnson, Feb 03 2013

Examples

			325 = 5^2*13, sum of primes between: 5+7+11+13 = 36, triangular; sum of composites between: 6+8+9+10+12 = 45, triangular.

Crossrefs

Cf. A000217, A074036, A074037.

Extensions

Offset corrected by Donovan Johnson, Feb 03 2013
Showing 1-3 of 3 results.

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

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