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.

A114026 n-th partial concatenation of A114025 divided by prime(n).

Original entry on oeis.org

1, 9, 55, 3931, 250161, 21167471, 161868896, 14483006487, 11964222750137, 9488866319074179, 8876681395262941651, 743721954738246462653, 67116371525158827117467, 6399467982631423050735227
Offset: 1

Views

Author

Amarnath Murthy, Nov 13 2005

Keywords

Examples

			a(2) = 27/3 = 9, a(3) 275/5 = 55, a(4) = 25717/7 = 3931.

Crossrefs

Cf. A114725.
Cf. A114025.

Extensions

More terms from R. J. Mathar, Jan 31 2008

A100759 Beginning with 2, least prime not occurring earlier such that the concatenation of first n terms has the least prime factor prime(n).

Original entry on oeis.org

2, 7, 5, 17, 127, 3, 347, 37, 71, 829, 89, 79, 311, 271, 1103, 823, 827, 7219, 149, 499, 3947, 6367, 2861, 3673, 13781, 2281, 281, 229, 353, 1597, 191, 1879, 2609, 10993, 19961, 4789, 383, 1093, 521, 13681, 9227, 12619, 8219, 12037, 8573, 7621, 6029
Offset: 1

Views

Author

Amarnath Murthy, Nov 23 2004

Keywords

Comments

Conjecture: Every prime is a member.

Examples

			a(1) = 2, a(2) = 7 and the least prime divisor of 27 is 3.

Crossrefs

Cf. A114025.

Programs

  • Mathematica
    a = {2}; b = 2; Do[i = 1; While[Length[Intersection[a, {Prime[i]}]] == 1, i++ ]; While[ !FactorInteger[FromDigits[Join[IntegerDigits[b], IntegerDigits[Prime[i]]]]][[1, 1]] == Prime[n], i++ ]; AppendTo[a, Prime[i]]; b = FromDigits[Join[IntegerDigits[b], IntegerDigits[Prime[i]]]], {n, 2, 30}]; a (* Stefan Steinerberger, Dec 21 2007 *)

Extensions

More terms from Stefan Steinerberger, Dec 21 2007
More terms from David Wasserman, Mar 04 2008

A135566 Least prime not already in the sequence such that the n-th partial concatenation is a multiple of the n-th prime.

Original entry on oeis.org

2, 7, 5, 17, 71, 23, 37, 137, 79, 241, 3, 173, 67, 31, 347, 433, 127, 47, 571, 1069, 107, 227, 229, 853, 647, 271, 83
Offset: 1

Views

Author

Amarnath Murthy, Nov 13 2005

Keywords

Crossrefs

See A114025 for another version.

Extensions

More terms from David Wasserman, Mar 04 2008
Showing 1-3 of 3 results.

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

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