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.

A230484 Strong pseudoprimes (base 2) that become prime when two is added.

Original entry on oeis.org

253241, 280601, 580337, 1207361, 1678541, 1909001, 2419385, 5173601, 16324001, 18073817, 22849481, 25080101, 43363601, 60155201, 67194401, 82870517, 85519337, 97924217, 100943201, 102004421, 104857391, 116090081, 128987429, 134696801, 135969401, 145348529
Offset: 1

Views

Author

Shyam Sunder Gupta, Oct 20 2013

Keywords

Examples

			253241 is a strong pseudoprime (base 2) and 253243 is prime.

Links

Crossrefs

Cf. A001262, A230483, A230485, A230487.

A230485 Strong pseudoprimes n to base 2 such that n-2 and n+2 are primes.

Original entry on oeis.org

3465253618401, 44202753561285411, 1640293473202755801, 10623546148468360251
Offset: 1

Views

Author

Shyam Sunder Gupta, Oct 20 2013

Keywords

Comments

For all n, a(n)-2 is in A230810. - M. F. Hasler, Dec 08 2016

Examples

			3465253618401 is a strong pseudoprime (base 2) and 3465253618399 and 3465253618403 are primes.

Crossrefs

Cf. A001567, A057942, A001262, A230483, A230484.

A230487 Strong pseudoprimes k to base 2 such that either k-2 or k+2 is prime.

Original entry on oeis.org

4681, 29341, 42799, 49141, 52633, 85489, 90751, 104653, 253241, 280601, 458989, 580337, 1004653, 1082401, 1207361, 1251949, 1302451, 1678541, 1907851, 1909001, 2419385, 2510569, 2811271, 3090091, 3539101, 5044033, 5049001, 5173601, 5489641, 5590621, 7177105
Offset: 1

Views

Author

Shyam Sunder Gupta, Oct 20 2013

Keywords

Examples

			4681 is a strong pseudoprime (base 2) and 4679 is prime. 253241 is a strong pseudoprime (base 2) and 253243 is prime.

Links

Crossrefs

Union of A230483 and A230484.
Cf. A001567, A001262, A230485.
Showing 1-3 of 3 results.

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