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.

A072055 a(n) = 2*prime(n)+1.

Original entry on oeis.org

5, 7, 11, 15, 23, 27, 35, 39, 47, 59, 63, 75, 83, 87, 95, 107, 119, 123, 135, 143, 147, 159, 167, 179, 195, 203, 207, 215, 219, 227, 255, 263, 275, 279, 299, 303, 315, 327, 335, 347, 359, 363, 383, 387, 395, 399, 423, 447, 455, 459, 467, 479
Offset: 1

Views

Author

Reinhard Zumkeller, Jun 11 2002

Keywords

Links

Crossrefs

Cf. A000040, A005385, A023589, A023590, A023591, A023592, A023593, A072059, A023595, A072060, A072056, A072057, A072058, A072192, A165286, A278230.
One less than A089241. After the initial term equal to A166496.
Row 4 of A286625, column 4 of A286623.

Programs

Formula

a(n) = A089241(n)-1.

A051614 4th term in Euclid-Mullin prime sequence started with n-th prime (cf. A000945).

Original entry on oeis.org

43, 43, 3, 43, 3, 79, 3, 5, 3, 3, 11, 223, 3, 7, 3, 3, 827, 367, 13, 3, 439, 5, 3, 3, 11, 5, 619, 3, 5, 3, 7, 3, 3, 5, 5, 907, 23, 11, 3, 3, 3, 1087, 3, 19, 3, 5, 7, 13, 3, 5, 3, 3, 1447, 3, 3, 3, 3767, 1627, 1663, 3, 1699, 3, 19, 5, 1879, 3, 1987, 7, 3, 5, 4943, 3, 2203, 2239, 5, 23
Offset: 1

Views

Author

Labos Elemer

Keywords

Comments

First term in Euclid-Mullin sequence is p (say), 2nd term (if p odd) is 2, 3rd term is A023592.

Examples

			E.g., (5,2,11,3), (89,2,179,3), (17,2,5,3), (2,3,7,43), (61,2,3,367).

Links

Crossrefs

Cf. A000945, A000040, A005384, A005385, A023592, A051308 - A051335.

Programs

  • Mathematica
    a[n_] := (Clear[f]; f[1] = Prime[n]; f[k_] := f[k] = FactorInteger[Product[f[i], {i, 1, k-1}]+1][[1, 1]]; f[4]); Table[a[n], {n, 1, 76}] (* Jean-François Alcover, Feb 05 2014 *)

A094460 a(n) is the third term in Euclid-Mullin (EM) prime sequence initiated with n-th prime.

Original entry on oeis.org

7, 7, 11, 3, 23, 3, 5, 3, 47, 59, 3, 3, 83, 3, 5, 107, 7, 3, 3, 11, 3, 3, 167, 179, 3, 7, 3, 5, 3, 227, 3, 263, 5, 3, 13, 3, 3, 3, 5, 347, 359, 3, 383, 3, 5, 3, 3, 3, 5, 3, 467, 479, 3, 503, 5, 17, 7, 3, 3, 563, 3, 587, 3, 7, 3, 5, 3, 3, 5, 3, 7, 719, 3, 3, 3, 13, 19, 3, 11, 3, 839, 3, 863
Offset: 1

Views

Author

Labos Elemer, May 06 2004

Keywords

Examples

			First term is p[n], 2nd equals 2; 3rd term is given here as largest p-divisor of 2p+1 [occasionally safe primes, A005385];
4th terms listed in A051614; further terms are in A094461-A094463.

Crossrefs

Cf. A000945, A005385, A051614-A051616, A051308 - A051335, A093778-A093782, A094152/A094153.
Except for first term [which is A000945(3)], the same as A023592.

Programs

  • Mathematica
    a[x_]:=First[Flatten [FactorInteger[Apply[Times, Table[a[j], {j, 1, x-1}]]+1]]]; ta=Table[0, {168}]; a[1]=1; Do[{a[1]=Prime[j], el=10}; Print[a[el]; ta[[j]]=a[el]; j++ ], {j, 1, 168}]; ta

Formula

a(n)= a(n-1)+ A008472(a(n-1)) - Ctibor O. Zizka, May 26 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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