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.

A222977 Smallest member of sociable quadruples with signature: abundant, deficient, abundant, deficient.

Original entry on oeis.org

18048976, 46722700, 4424606020, 73636082872, 88585861815, 90568599176, 518833084192, 1138168194296, 5793575538465
Offset: 1

Views

Author

Michel Marcus, Mar 11 2013

Keywords

Comments

See comments in A222975.
1216327163895122388615 and 12015582455500352695694 are also terms. - Amiram Eldar, Apr 05 2024

Examples

			The first quadruple of this type is: 18048976, 20100368, 18914992, 19252208, that are respectively abundant, deficient, abundant, deficient.
		

Crossrefs

Extensions

a(8)-a(9) from Amiram Eldar, Apr 05 2024

A222975 Smallest member of sociable quadruples with signature: abundant, abundant, deficient, deficient.

Original entry on oeis.org

1264460, 2115324, 2784580, 7169104, 18656380, 28158165, 81128632, 174277820, 498215416, 1236402232, 1799281330, 2387776550, 2717495235, 2879697304, 15837081520, 17616303220, 91411869465, 111375706442, 661126361272, 741158497112, 1045805730255, 1092162882824
Offset: 1

Views

Author

Michel Marcus, Mar 11 2013

Keywords

Comments

Members of a sociable quadruple are usually listed in the order with which they appear in the corresponding aliquot sequence. Therefore, in a sociable quadruple the 1st member is abundant, and the 4th member is deficient. In all, we can get 4 possibilities, and a sociable quadruple can be (with A for abundant, and D for deficient) : AADD, ADDD, ADAD, AAAD. The numbers in these sequences have been voluntarily limited to 12 digits maximum, the current status of the exhaustive search (see Pedersen link).

Examples

			The first quadruple of this type is: 1264460, 1547860, 1727636, 1305184, that are respectively abundant, abundant, deficient, deficient.
		

Crossrefs

Extensions

a(21)-a(22) from Amiram Eldar, Apr 05 2024

A222978 Smallest member of sociable quadruples with signature: abundant, abundant, abundant, deficient.

Original entry on oeis.org

330003580, 3705771825, 5373457070
Offset: 1

Views

Author

Michel Marcus, Mar 11 2013

Keywords

Comments

See comments in A222975.
a(4) > 10^14, if it exists. - Amiram Eldar, Apr 05 2024

Examples

			The first quadruple of this type is: 330003580, 363003980, 399304420, 440004764 that are respectively abundant, abundant, abundant, deficient.
		

Crossrefs

Showing 1-3 of 3 results.