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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A239477 Smallest number with additive and multiplicative persistence equal to n.

Original entry on oeis.org

0, 10, 28, 289, 2488888888888888999999999
Offset: 0

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Author

Giovanni Resta, Mar 20 2014

Keywords

Comments

The corresponding smallest primes are 2, 11, 29, 487 and 2488888888888898999989999.

Examples

			a(3) = 289 because 289 is the smallest number with additive persistence 3, 289 -> 19 -> 10 -> 1 and multiplicative persistence 3, 289 -> 144 -> 16  -> 6.

Crossrefs

Cf. A031346, A003001, A031286, A006050, A239427.

A239486 Smallest palindrome which has additive and multiplicative persistence n.

Original entry on oeis.org

0, 11, 99, 595, 467778888888979888888877764
Offset: 0

Views

Author

Giovanni Resta, Mar 20 2014

Keywords

Comments

The corresponding sequence made of palindromic primes begins with 2, 11, 12421, 757 and 746788887898878898788887647.

Examples

			a(595) since 595 is the smallest palindrome with additive persistence 3 (595 -> 19 -> 10 -> 1) and multiplicative persistence 3 (595 -> 225 -> 20 -> 0).

Crossrefs

Cf. A031346, A003001, A031286, A006050, A201991, A239427.

A319507 Smallest number of multiplicative-additive divisors persistence n.

Original entry on oeis.org

1, 2, 36, 3489, 24778899, 566677899999, 47777778999999999999
Offset: 0

Views

Author

Pieter Post, Sep 21 2018

Keywords

Comments

To compute the "multiplicative-additive divisors persistence" of a number, we proceed as follows. Form the product of the digits of the number (A007954) divided by the sum of the digits (A007953). Repeat this process until you reach 0 or 1. If we reach a non-integer, we write 0. The "multiplicative-additive divisors persistence" is the number of steps to reach 0 or 1.
For instance: the multiplicative-additive divisors persistence of 874 is 1, because 874 -> 8 * 7 * 4 / (8 + 7 + 4) = 224/19. This is not an integer, so the process stops after one step.

Examples

			The multiplicative additive divisors persistence of 24778899 is 4: 24778899 -> (2032128/54=) 37632 -> (756/21=) 36 -> (18/9=) 2 -> (2/2=) 1.

Crossrefs

Cf. A038367, A126789, A003001, A006050, A007953, A007954, A031346.

Extensions

Offset set to 0. - R. J. Mathar, Jun 30 2020
Previous Showing 11-13 of 13 results.

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