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 1-4 of 4 results.

A069460 Greatest prime factor of prime(n)^n - 1.

Original entry on oeis.org

2, 31, 5, 3221, 157, 25646167, 3833, 7792003, 732541, 150332843, 144061, 17615988547, 6177695707, 461017351, 31129845205681, 361353204962363828785531, 903870199, 751410597400064602523400427092397, 25058741, 153436090543, 1750258119644519
Offset: 2

Views

Author

Reinhard Zumkeller, Mar 24 2002

Keywords

Examples

			A000040(9)^9 - 1 = 23^9 - 1 = 1801152661462 = 2*7*11*19*79*7792003, therefore a(9) = 7792003.
		

Crossrefs

Programs

  • Mathematica
    Table[FactorInteger[Prime[n]^n-1][[-1,1]],{n,2,30}] (* Harvey P. Dale, May 19 2019 *)

Formula

a(n) = A006530(A069459(n)).

Extensions

More terms from Hugo Pfoertner, May 18 2004
Undefined a(1) removed by Hugo Pfoertner, Jul 22 2019

A069461 Number of distinct prime factors of prime(n)^n-1.

Original entry on oeis.org

0, 1, 2, 3, 3, 5, 2, 6, 6, 8, 7, 11, 5, 7, 9, 8, 5, 12, 4, 13, 8, 10, 4, 16, 7, 12, 12, 13, 6, 18, 4, 15, 10, 8, 10, 19, 8, 9, 8, 17, 5, 21, 5, 13, 16, 16, 6, 21, 9, 12, 9, 15, 10, 20, 9, 22, 9, 17, 7, 31, 7, 11, 13, 21, 9, 17, 11, 16, 14, 21, 5, 32, 7, 12, 16
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 24 2002

Keywords

Examples

			A000040(8)^8-1 = 19^8 - 1 = 16983563040 = 2^5*3^2*5*17*181*3833, therefore a(8) = 6 and A069462(8) = 11.
A000040(9)^9-1 = 23^9-1 = 1801152661462 = 2*7*11*19*79*7792003, therefore a(9) = 6 and A069462(9) = 6.
		

Crossrefs

Programs

  • Mathematica
    Table[PrimeNu[Prime[n]^n - 1], {n, 1, 30}] (* Amiram Eldar, Feb 17 2020 *)
  • PARI
    for(n=1,52,print1(omega(prime(n)^n-1)",")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

Formula

a(n) = A001221(A069459(n)).

Extensions

More terms from Hugo Pfoertner, May 18 2004
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(53)-a(75) using factordb.com from Amiram Eldar, Feb 17 2020

A069462 Number of prime factors of prime(n)^n-1, with multiplicity.

Original entry on oeis.org

0, 3, 3, 8, 4, 8, 5, 11, 6, 11, 7, 16, 7, 10, 9, 15, 5, 16, 4, 19, 12, 14, 4, 24, 11, 15, 15, 19, 9, 23, 5, 22, 12, 10, 11, 26, 9, 14, 8, 22, 5, 26, 5, 22, 18, 21, 6, 30, 9, 16, 11, 24, 13, 28, 17, 27, 10, 23, 8, 37, 7, 14, 16, 29, 12, 20, 11, 22, 14, 26, 9, 40
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 24 2002

Keywords

Examples

			A000040(8)^8-1 = 19^8-1 = 16983563040 = 2^5*3^2*5*17*181*3833, therefore a(8) = 11 and A069461(8) = 6.
A000040(9)^9-1 = 23^9-1 = 1801152661462 = 2*7*11*19*79*7792003, therefore a(9) = 6 and A069461(9) = 6.
		

Crossrefs

Programs

  • Mathematica
    Table[PrimeOmega[Prime[n]^n - 1], {n, 1, 30}] (* Amiram Eldar, Feb 17 2020 *)
  • PARI
    for(n=1,52,print1(bigomega(prime(n)^n-1)",")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

Formula

a(n) = A001222(A069459(n)).

Extensions

More terms from Hugo Pfoertner, May 21 2004
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
a(53)-a(72) using factordb.com from Amiram Eldar, Feb 17 2020

A319074 a(n) is the sum of the first n nonnegative powers of the n-th prime.

Original entry on oeis.org

1, 4, 31, 400, 16105, 402234, 25646167, 943531280, 81870575521, 15025258332150, 846949229880161, 182859777940000980, 23127577557875340733, 1759175174860440565844, 262246703278703657363377, 74543635579202247026882160, 21930887362370823132822661921, 2279217547342466764922495586798
Offset: 1

Views

Author

Omar E. Pol, Sep 11 2018

Keywords

Examples

			For n = 4 the 4th prime is 7 and the sum of the first four nonnegative powers of 7 is 7^0 + 7^1 + 7^2 + 7^3 = 1 + 7 + 49 + 343 = 400, so a(4) = 400.
		

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n-1, prime(n)^k); \\ Michel Marcus, Sep 13 2018

Formula

a(n) = Sum_{k=0..n-1} A000040(n)^k.
a(n) = Sum_{k=0..n-1} A319075(k,n).
a(n) = (A000040(n)^n - 1)/(A000040(n) - 1).
a(n) = (A062457(n) - 1)/A006093(n).
a(n) = A069459(n)/A006093(n).
a(n) = A000203(A000040(n)^(n-1)).
a(n) = A000203(A093360(n)).
Showing 1-4 of 4 results.