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 1-9 of 9 results.

A085752 Duplicate of A074966.

Original entry on oeis.org

1, 1, 2, 1, 12, 7, 4, 43, 10, 19, 62, 35, 16, 27, 28, 13, 74, 107, 18, 91, 32, 87, 14, 95, 96
Offset: 1

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Author

Keywords

A074967 a(n) = least k such that n^n - k is prime.

Original entry on oeis.org

1, 4, 5, 4, 7, 2, 3, 10, 33, 42, 19, 12, 17, 52, 59, 18, 65, 2, 51, 2, 23, 120, 35, 2, 63, 10, 39, 186, 7, 74, 47, 200, 53, 24, 19, 48, 333, 56, 57, 192, 127, 348, 63, 124, 213, 60, 359, 2, 213, 2, 387, 526, 269, 252, 863, 16, 131, 370, 503, 294, 83, 68, 317
Offset: 2

Views

Author

Zak Seidov, Oct 03 2002

Keywords

Crossrefs

Programs

  • Mathematica
    PrimePrevDelta[n_]:=Module[{k},k=n-1;While[ !PrimeQ[k],k-- ];k=n-k]; lst={};Do[AppendTo[lst,PrimePrevDelta[n^n]],{n,2,5!}];lst (* Vladimir Joseph Stephan Orlovsky, Jun 11 2009 *)
    lk[n_]:=Module[{nn=n^n},nn-NextPrime[nn,-1]]; Array[lk,70,2] (* Harvey P. Dale, Jan 20 2019 *)
  • PARI
    a(n)=(x->x-precprime(x))(n^n) \\ Charles R Greathouse IV, Nov 25 2014

Extensions

More terms from Robert G. Wilson v, Oct 04 2002
Offset corrected by R. J. Mathar, Jun 12 2009

A098682 Smallest prime larger than n^n.

Original entry on oeis.org

2, 5, 29, 257, 3137, 46663, 823547, 16777259, 387420499, 10000000019, 285311670673, 8916100448291, 302875106592269, 11112006825558043, 437893890380859403, 18446744073709551629, 827240261886336764251, 39346408075296537575531, 1978419655660313589123997
Offset: 1

Views

Author

Olaf Voß, Oct 27 2004

Keywords

Crossrefs

Programs

Formula

a(n) = A074966(n) + n^n. - Michel Marcus, Mar 11 2020

A161503 a(n) = NextPrime(n^n) - PrevPrime(n^n).

Original entry on oeis.org

2, 6, 6, 16, 14, 6, 46, 20, 52, 104, 54, 28, 44, 80, 72, 92, 172, 20, 142, 34, 110, 134, 130, 98, 106, 78, 174, 306, 26, 132, 54, 258, 116, 78, 50, 90, 448, 66, 214, 302, 140, 352, 466, 246, 670, 594, 396, 20, 244, 228, 640, 546, 462, 354, 1040, 408, 176, 564, 760
Offset: 2

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Author

Keywords

Examples

			3 <- 2^2 -> 5; 5 - 3 = 2;
23 <- 3^3 -> 29; 29 - 23 = 6.
		

Crossrefs

Programs

  • Maple
    for n from 2 to 100 do nn := n^n ; printf("%d,",nextprime(nn)-prevprime(nn) ) ; od: # R. J. Mathar, Jun 12 2009
  • Mathematica
    PrimeNext[n_]:=Module[{k},k=n+1;While[ !PrimeQ[k],k++ ];k]; PrimePrev[n_]:=Module[{k}, k=n-1;While[ !PrimeQ[k],k-- ];k]; DeltaY[n_]:=PrimeNext[n]-PrimePrev[n]; lst={};Do[AppendTo[lst,DeltaY[n^n]],{n,2,5!}];lst
    npnn[n_]:=Module[{nn=n^n},NextPrime[nn]-NextPrime[nn,-1]]; Array[npnn,60,2] (* Harvey P. Dale, Dec 07 2013 *)

Formula

a(n) = A074966(n) + A074967(n) = A013633(A000312(n)). - R. J. Mathar, Jun 12 2009

Extensions

Offset changed by R. J. Mathar, Jun 12 2009

A333184 a(n) = n^n - (PrevPrime(n^n) + NextPrime(n^n)) / 2.

Original entry on oeis.org

0, 1, 2, -4, 0, -1, -20, 0, 7, -10, -8, -2, -5, 12, 23, -28, -21, -8, -20, -15, -32, 53, -30, -47, 10, -29, -48, 33, -6, 8, 20, 71, -5, -15, -6, 3, 109, 23, -50, 41, 57, 172, -170, 1, -122, -237, 161, -8, 91, -112, 67, 253, 38, 75, 343, -188, 43, 88, 123, 96
Offset: 2

Views

Author

Hugo Pfoertner, Mar 10 2020

Keywords

Examples

			   n Previous P      n^n       Next P    a(n)
     A098681(n)  A000312(n)  A098682(n)
   2          3           4           5   0
   3         23          27          29   1
   4        251         256         257   2
   5       3121        3125        3137  -4
   6      46649       46656       46663   0
   7     823541      823543      823547  -1
   8   16777213    16777216    16777259 -20
   9  387420479   387420489   387420499   0
  10 9999999967 10000000000 10000000019   7
		

Crossrefs

Cf. A333185 (position of terms = 0).

Programs

  • Maple
    a:= n-> (m-> m-(prevprime(m)+nextprime(m))/2)(n^n):
    seq(a(n), n=2..65);  # Alois P. Heinz, Mar 10 2020
  • PARI
    for(n=2,61, my(f=n^n); print1(f-(precprime(f)+nextprime(f))/2,", "))

A300292 Numbers k such that k^k + 9 is a prime.

Original entry on oeis.org

2, 130, 140
Offset: 1

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Author

Seiichi Manyama, Mar 16 2018

Keywords

Comments

No more terms <= 7000. - Jon E. Schoenfield, Mar 16 2018
No more terms <= 30000. - Michael S. Branicky, Sep 02 2024

Crossrefs

Numbers k such that k^k + b is a prime: A300981 (b=-10), A300976 (b=-5), A100408 (b=-2), A100407 (b=2), A166852 (b=3), A100837 (b=4), A100838 (b=7), this sequence (b=9), A100839 (b=10), A173974 (b=43).
Cf. A074966.

Programs

  • PARI
    isok(k) = ispseudoprime(k^k + 9); \\ Altug Alkan, Mar 16 2018

A103111 Smallest natural number m such that n^n^n + m is prime.

Original entry on oeis.org

1, 1, 16, 75, 2994, 96545
Offset: 1

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Author

Farideh Firoozbakht, Mar 04 2005

Keywords

Examples

			a(5)=2994 because 5^5^5 + 2994 is prime and 5^5^5 + k is composite for 0<k<2994.
		

Crossrefs

Programs

Extensions

a(6) from Donovan Johnson, Mar 06 2008

A103112 Smallest natural number m such that n^n^n - m is a prime.

Original entry on oeis.org

3, 26, 569, 10978, 106843
Offset: 2

Views

Author

Farideh Firoozbakht, Mar 04 2005

Keywords

Examples

			a(5)=10978 because 5^5^5 - 10978 is a prime and 5^5^5 - k is composite for 0<k<10978.
		

Crossrefs

Programs

Extensions

a(6) from Donovan Johnson, Mar 06 2008

A333185 Numbers k such that k^k is the average of its nearest 2 primes.

Original entry on oeis.org

2, 6, 9, 940
Offset: 1

Views

Author

Hugo Pfoertner, Mar 11 2020

Keywords

Examples

			          Previous P         k^k           Next P
  a(n)  A098681(a(n))  A000312(a(n))  A098682(a(n))
    2               3              4              5
    6           46649          46656          46663
    9       387420479      387420489      387420499
  940    940^940-3063        940^940   940^940+3063
		

Crossrefs

Programs

  • PARI
    isok(k) = if (k>1, my(x=k^k); precprime(x-1)+nextprime(x+1) == 2*x); \\ Michel Marcus, Mar 14 2020

Formula

A333184(a(n)) = 0.
A074966(a(n)) = A074967(a(n)).
Showing 1-9 of 9 results.