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.

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A236226 Sum of the eighteenth powers of the first n primes.

Original entry on oeis.org

262144, 387682633, 3815084948258, 1632228682858707, 5561549542175090188, 118016956494132483317, 14181101408561857474326, 118308451706473099007167, 3362459361601721384307536, 213819743726773841714612697, 912873363725818880253782938
Offset: 1

Views

Author

Robert Price, Jan 20 2014

Keywords

Crossrefs

Cf. A085450 = smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n.
Partial sums of A030637.

Programs

  • Mathematica
    Table[Sum[Prime[k]^18, {k, n}], {n, 1000}]
    Accumulate[Prime[Range[20]]^18] (* Harvey P. Dale, Jul 08 2024 *)

Formula

a(n) = sum(k = 1 .. n, prime(k)^18).

A236227 Sum of the nineteenth powers of the first n primes.

Original entry on oeis.org

524288, 1162785755, 19074649113880, 11417969834487023, 61170508418249033314, 1523090798793695143991, 240595526483945019991144, 2219015182144258609115123, 76834486109734969171023610, 6180095732699726458749873279, 27850757952670122653464150750
Offset: 1

Views

Author

Robert Price, Jan 20 2014

Keywords

Crossrefs

Cf. A085450 = smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n.

Programs

  • Mathematica
    Table[Sum[Prime[k]^19, {k, n}], {n, 1000}]

Formula

a(n) = sum(k = 1 .. n, prime(k)^19).

A160759 Integer averages of n values of pi(n^2) for some n, where pi(n) is the number of primes <= n.

Original entry on oeis.org

0, 1, 2, 3, 201, 235, 265, 431, 1705, 11744, 33946, 622755, 3446493, 8134880, 14287916, 208340425, 223689468
Offset: 1

Views

Author

Daniel Tisdale, May 25 2009

Keywords

Comments

For values of n: 1, 2, 3, 4, 62, 68, 73, 97, 213, 624, 1116, 5364, 13350, 21048, 28351, 116151, 120562, ..., . [Robert G. Wilson v, Jun 05 2009]

Crossrefs

Cf. A050248, Integer averages of n primes for some n.

Programs

  • Mathematica
    lst = {}; s = 0; k = 1; While[k < 239600, s = s + PrimePi[k^2]; If[ Mod[s, k] == 0, AppendTo[lst, s/c]]; k++ ]; lst (* Robert G. Wilson v, Jun 05 2009 *)

Formula

1/k*Sum {j=1..k} Pi(j^2) is an integer. [Robert G. Wilson v, Jun 05 2009]

Extensions

More terms from Robert G. Wilson v, Jun 05 2009

A164619 Integers of the form A164577(k)/3.

Original entry on oeis.org

4, 15, 54, 75, 132, 169, 320, 459, 735, 847, 1104, 1250, 1764, 2175, 2904, 3179, 3780, 4107, 5200, 6027, 7425, 7935, 9024, 9604, 11492, 12879, 15162, 15979, 17700, 18605, 21504, 23595, 26979, 28175, 30672, 31974, 36100, 39039, 43740, 45387, 48804
Offset: 1

Views

Author

Keywords

Comments

The sequence members are the third of the average of a set of smallest cubes, if integer.

Examples

			A third of the average of the first cube, A164577(1)/3=1/3, is not an integer and does not contribute to the sequence.
A third of the average of the first two cubes, A164577(2)/3=4, is an integer and defines a(1)=4 of the sequence.
		

Crossrefs

Programs

  • Mathematica
    s=0;lst={};Do[a=(s+=(n^3)/3)/n;If[Mod[a,1]==0,AppendTo[lst,a]],{n,2*5!}]; lst
    LinearRecurrence[{2,-1,-1,2,-1,2,-4,2,2,-4,2,-1,2,-1,-1,2,-1},{4,15,54,75,132,169,320,459,735,847,1104,1250,1764,2175,2904,3179,3780},50] (* Harvey P. Dale, Apr 06 2016 *)
  • PARI
    Vec(x*(x^14 +x^13 +16*x^12 +10*x^11 +47*x^10 -22*x^9 +61*x^8 +10*x^7 +88*x^6 +8*x^5 +43*x^4 -14*x^3 +28*x^2 +7*x +4) / ((x -1)^4*(x +1)^3*(x^2 -x +1)^3*(x^2 +x +1)^2) + O(x^100)) \\ Colin Barker, Oct 27 2014

Formula

a(n) = +2*a(n-1) -a(n-2) -a(n-3) +2*a(n-4) -a(n-5) +2*a(n-6) -4*a(n-7) +2*a(n-8) +2*a(n-9) -4*a(n-10) +2*a(n-11) -a(n-12) +2*a(n-13) -a(n-14) -a(n-15) +2*a(n-16) -a(n-17). - R. J. Mathar, Jan 25 2011
G.f.: x*(x^14 +x^13 +16*x^12 +10*x^11 +47*x^10 -22*x^9 +61*x^8 +10*x^7 +88*x^6 +8*x^5 +43*x^4 -14*x^3 +28*x^2 +7*x +4) / ((x -1)^4*(x +1)^3*(x^2 -x +1)^3*(x^2 +x +1)^2). - Colin Barker, Oct 27 2014

Extensions

Edited by R. J. Mathar, Aug 20 2009

A221867 Let m = A153022(n); a(n) = (1 + sum_{i=1..m} prime(i)^2)/(1+m).

Original entry on oeis.org

54, 218, 222054, 669806, 155593313228, 31860927184920, 37843679840313254, 5349233671440437948, 65075392901385088766, 102744428793110424984, 251471854505406311064463, 1074272348712875302655077, 1114427338015137279788981
Offset: 1

Views

Author

Robert Price, Apr 10 2013

Keywords

Examples

			For n=2, m=10, a(2) = 2398/11=218.
		

Crossrefs

Extensions

Definition corrected by N. J. A. Sloane, Apr 20 2013

A232770 Prime(k), where k is such that (Sum_{i=1..k} prime(i)^13) / k is an integer.

Original entry on oeis.org

2, 83, 1979, 2081, 2326469, 6356923, 7170679, 63812027, 4652001719, 241949473277, 163220642765623, 1260677492111911, 8150959175977039
Offset: 1

Views

Author

Robert Price, Nov 29 2013

Keywords

Comments

a(13) > 1352363608564489. - Bruce Garner, Aug 30 2021
a(14) > 18205684894350047. - Paul W. Dyson, Dec 06 2024

Examples

			a(2) = 83, because 83 is the 23rd prime and the sum of the first 23 primes^13 = 17226586990098074754709144 when divided by 23 equals 748982043047742380639528 which is an integer.
		

Crossrefs

Cf. A085450 (smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n).

Programs

  • Mathematica
    t = {}; sm = 0; Do[sm = sm + Prime[n]^13; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)
  • PARI
    is(n)=if(!isprime(n),return(0)); my(t=primepi(n),s); forprime(p=2,n,s+=Mod(p,t)^13); s==0 \\ Charles R Greathouse IV, Nov 30 2013

Extensions

a(11) from Bruce Garner, Mar 23 2021
a(12) from Bruce Garner, Aug 30 2021
a(13) from Paul W. Dyson, Apr 20 2023

A232848 Prime(k), where k divides Sum_{i=1..k} prime(i)^15.

Original entry on oeis.org

2, 59, 97, 127, 12517, 54581, 83921, 89273, 1396411, 2562719, 4952183, 29201281, 35562101, 47567557, 111213143, 184201627, 1172476337, 7309217299, 287609314877, 5173838081669, 408907258717171, 1357729730868191, 66413899001789557
Offset: 1

Views

Author

Robert Price, Dec 09 2013

Keywords

Examples

			a(2) = 59, because 59 is the 17th prime and the sum of the first 17 primes^15 = 455708280934100194626604550 when divided by 17 equals 26806369466711776154506150 which is an integer.
		

Crossrefs

Cf. A085450 (smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n), A131275.

Programs

  • Mathematica
    t = {}; sm = 0; Do[sm = sm + Prime[n]^15; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)
  • PARI
    is(n)=if(!isprime(n),return(0)); my(t=primepi(n),s); forprime(p=2,n,s+=Mod(p,t)^15); s==0 \\ Charles R Greathouse IV, Nov 30 2013
    
  • PARI
    S=n=0;forprime(p=1,,(S+=p^15)%n++||print1(p",")) \\ M. F. Hasler, Dec 01 2013

Formula

a(n) = prime(A131275(n)).

Extensions

a(20) from Karl-Heinz Hofmann, Feb 17 2021
a(21) from Bruce Garner, Apr 30 2021
a(22) from Bruce Garner, Jan 07 2022
a(23) from Paul W. Dyson, Apr 18 2024

A232963 Prime(m), where m is such that (sum_{i=1..m} prime(i)^14) / m is an integer.

Original entry on oeis.org

2, 1933, 3217, 41681, 114311, 2743691233, 7252463461, 28682755720447, 2839633449523319
Offset: 1

Views

Author

Robert Price, Dec 02 2013

Keywords

Comments

The primes correspond to indices n = 1, 295, 455, 4361, 10817, 132680789, 334931875, 957643538339 = A131274.
a(10) > 7.6*10^16. - Paul W. Dyson, Jan 17 2025

Examples

			a(2) = 1933, because 1193391 is the 295th prime and the sum of the first 295 primes^14 = 172657243368537051859007103457435197295421033550 when divided by 295 equals 585278791079786616471210520194695584052274690 which is an integer.
		

Crossrefs

Cf. A085450 = smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n.

Programs

  • Mathematica
    t = {}; sm = 0; Do[sm = sm + Prime[n]^14; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)
  • PARI
    is(n)=if(!isprime(n),return(0)); my(t=primepi(n),s); forprime(p=2,n,s+=Mod(p,t)^14); s==0 \\ Charles R Greathouse IV, Nov 30 2013
    
  • PARI
    S=n=0;forprime(p=1,,(S+=p^14)%n++||print1(p",")) \\ M. F. Hasler, Dec 01 2013

Formula

a(n) = prime(A131274(n)).

Extensions

a(8) from Paul W. Dyson, Jan 03 2021
a(9) from Bruce Garner, Mar 28 2022

A233192 Prime(k), where k is such that (Sum_{j=1..k} prime(j)^11) / k is an integer.

Original entry on oeis.org

2, 97, 277, 23311, 61583, 6133811, 210952097, 359643241, 5451597181, 42641466149, 51575229001, 199655689679, 248181386429, 61646670874849, 82153230089767, 212374157550341, 11432141933990629, 15031011453909223
Offset: 1

Views

Author

Robert Price, Dec 05 2013

Keywords

Comments

a(17) > 257180056649941. - Bruce Garner, Mar 29 2021
a(19) > 18205684894350047. - Paul W. Dyson, Jan 16 2025

Examples

			a(2) = 97, because 97 is the 25th prime and the sum of the first 25 primes^11 = 12718098700540100969050 when divided by 25 equals 508723948021604038762 which is an integer.
		

Crossrefs

Cf. A085450 = smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n.

Programs

  • Mathematica
    t = {}; sm = 0; Do[sm = sm + Prime[n]^11; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)
  • PARI
    is(n)=if(!isprime(n),return(0)); my(t=primepi(n),s); forprime(p=2,n,s+=Mod(p,t)^11); s==0 \\ Charles R Greathouse IV, Nov 30 2013
    
  • PARI
    S=n=0;forprime(p=1,,(S+=p^11)%n++||print1(p",")) \\ M. F. Hasler, Dec 01 2013

Formula

a(n) = prime(A125827(n)).

Extensions

a(14) from Paul W. Dyson, Jan 08 2021
a(15) from Bruce Garner, Mar 08 2021
a(16) from Bruce Garner, Mar 29 2021
a(17) from Paul W. Dyson, Jan 03 2023
a(18) from Paul W. Dyson, Dec 20 2024

A233460 Prime(n), where n is such that (sum_{i=1..n} prime(i)^16) / n is an integer.

Original entry on oeis.org

2, 28751, 62639, 4620757, 6478193, 2298168044423, 128195718927553
Offset: 1

Views

Author

Robert Price, Dec 10 2013

Keywords

Comments

a(8) > 128971810356197. - Bruce Garner, Mar 24 2021
a(8) > 7.6*10^16. - Paul W. Dyson, Nov 27 2024

Examples

			a(1) = 2, because 2 is the 1st prime and the sum of the first 1 primes^16 = 65536 when divided by 1 equals 65536 which is an integer.
		

Crossrefs

Cf. A085450 (smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n).

Programs

  • Mathematica
    t = {}; sm = 0; Do[sm = sm + Prime[n]^16; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)
  • PARI
    is(n)=if(!isprime(n),return(0)); my(t=primepi(n),s); forprime(p=2,n,s+=Mod(p,t)^16); s==0 \\ Charles R Greathouse IV, Nov 30 2013
    
  • PARI
    S=n=0;forprime(p=1,,(S+=p^16)%n++||print1(p",")) \\ M. F. Hasler, Dec 01 2013

Formula

a(n) = prime(A131276(n)).

Extensions

a(6)-a(7) from Bruce Garner, Mar 24 2021
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