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.

A111478 Primes pertaining to A111477.

Original entry on oeis.org

11, 111919, 111919191919, 11191919191937373737, 111919191919373737372121212121, 111919191919373737372121212121717171717171, 111919191919373737372121212121717171717171101101101101101101101
Offset: 1

Views

Author

Amarnath Murthy, Aug 05 2005

Keywords

Examples

			111919191919 = one copy of 11, two copies of 19, three copies of 19.

Crossrefs

Cf. A111471, A111472, A111473, A111474, A111475, A111477.

Extensions

More terms from Tracy Poff (tracy.poff(AT)gmail.com), Dec 31 2005

A111479 a(n) = least positive number such that (2 Concat Concat_{k=1}^n Repeat(A045572(n), a(n))) is a prime. A045572 = odd numbers not divisible by 5.

Original entry on oeis.org

2, 1, 4, 11, 3, 617, 96, 1213, 1965
Offset: 1

Views

Author

Amarnath Murthy, Aug 05 2005

Keywords

Comments

Concat is the operator that concatenates two numbers as decimal strings and Repeat returns the number obtained by concatenating the first argument to itself the second argument number of times.

Examples

			21 is not a prime, but 211 is, so a(1)=2.
211,2113,21137777 are all primes. 21137777 is a prime obtained as 2 followed by two 1's, one 3 and four 7's, so a(2) = 4.

Crossrefs

Cf. A111471, A111472, A111473, A111475, A111477, A111478, A111480.

Extensions

Edited by Franklin T. Adams-Watters, Aug 29 2006.
Corrected and extended by Max Alekseyev, May 21 2009

A111480 Primes pertaining to A111479.

Original entry on oeis.org

211, 2113, 21137777, 2113777799999999999, 2113777799999999999111111
Offset: 1

Views

Author

Amarnath Murthy, Aug 05 2005

Keywords

Comments

The next term is 21137777999999999991111111313...13 where the number of trailing 13's is 617. It has 1259 decimal digits.

Crossrefs

Cf. A111471, A111472, A111473, A111474, A111475, A111477, A111478, A111479.

Extensions

Corrected by Max Alekseyev, May 21 2009
Showing 1-3 of 3 results.

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

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