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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A282773 Numbers n such that Bernoulli number B_{n} has denominator 498.

Original entry on oeis.org

82, 574, 1066, 1394, 3034, 3362, 3854, 4838, 5494, 5822, 6478, 7462, 7954, 8282, 8774, 8938, 10414, 11234, 12218, 12382, 12874, 13694, 15826, 16154, 17302, 18614, 18778, 21074, 21238, 21566, 22058, 22222, 22714, 23206, 23534, 23698, 25174, 25502, 25994
Offset: 1

Views

Author

Paolo P. Lava, Mar 07 2017

Keywords

Comments

498 = 2 * 3 * 83.
All terms are multiples of a(1) = 82.
For these numbers numerator(B_{n}) mod denominator(B_{n}) = 77.
n such that 82 | n but there are no primes p other than 2, 3, 83 such that p-1 | n. - Robert Israel, Mar 07 2017

Examples

			Bernoulli B_{82} is 1677014149185145836823154509786269900207736027570253414881613/498, hence 82 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q,h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6,498);
    # Alternative:
    filter:= n ->
      select(isprime,map(`+`,numtheory:-divisors(n),1)) = {2,3,83}:
    select(filter, [seq(i,i=82..10^5,82)]); # Robert Israel, Mar 07 2017
  • Mathematica
    Select[82 Range[360], Denominator@ BernoulliB@ # == 498 &] (* Michael De Vlieger, Mar 07 2017 *)

Extensions

More terms from Michael De Vlieger, Mar 07 2017

A119657 Denominator of BernoulliB[10p] divided by 66, where p=Prime[n].

Original entry on oeis.org

5, 217, 1, 71, 23, 131, 1, 191, 47, 59, 311, 1, 83, 431, 1, 107, 1, 1, 1, 1, 1, 1, 167, 179, 971, 1, 1031, 1, 1091, 227, 1, 263, 1, 1, 1, 1511, 1571, 1, 1, 347, 359, 1811, 383, 1931, 1, 1, 2111
Offset: 1

Views

Author

Alexander Adamchuk, Jul 28 2006

Keywords

Comments

The only composite in this sequence is a(2) = 217 = 7*31. All other a(n) are equal to 1 (for n=3,7,12,15,17,18,19,20,21,22,26,28,31,33,34,35,38,39,45,46..) or prime: a(1) = 5, all other primes in a(n) belong to A068231[n]: Primes congruent to 11 (mod 12). It appears that every prime from A068231[n] except 11 shows up in a(n) just once.

Crossrefs

Programs

  • Mathematica
    Table[Denominator[BernoulliB[10Prime[n]]]/66,{n,1,47}]

Formula

a(n) = Denominator[BernoulliB[10Prime[n]]]/66.

A249306 Denominators A027642(n) of Bernoulli numbers except for a(4*k+5)=2 instead of 1.

Original entry on oeis.org

1, 2, 6, 1, 30, 2, 42, 1, 30, 2, 66, 1, 2730, 2, 6, 1, 510, 2, 798, 1, 330, 2, 138, 1, 2730, 2, 6, 1, 870, 2, 14322, 1, 510, 2, 6, 1, 1919190, 2, 6, 1, 13530, 2, 1806, 1, 690, 2, 282, 1, 46410, 2, 66, 1, 1590, 2, 798, 1, 870, 2, 354, 1
Offset: 0

Views

Author

Paul Curtz, Oct 28 2014

Keywords

Comments

There exist an infinity of 1's, 2's, 6's, 30's, 42's, 66's, ... .
Respective ranks:
0, 3, 7, 11, 15, 19, ...
1, 5, 9, 13, 17, 21, ... (= A016813)
2, 14, 26, 34, 38, 62, ... (= A051222)
4, 8, 68, 76, 124, 152, ... (= A051226)
6, 114, 186, 258, 354, 402, ... (= A051228)
10, 50, 170, 370, 470, 590, ... (= A051230)
12, 24, 1308, 1884, 2004, 2364, ... (= A249134)
etc.
Hence by antidiagonals a permutation of A001477(n).
First column: A248614(n).
a(n) is an alternative sequence for the denominators of the Bernoulli numbers.
First 36 terms of the corresponding clockwise spiral:
.
330------2----138------1---2730------2
| |
| |
1 42------1-----30------2 6
| | | |
| | | |
798 2 1------2 66 1
| | | | |
| | | | |
2 30------1------6 1 870
| | |
| | |
510------1------6------2---2730 2
|
|
1------6------2----510------1--14322

Crossrefs

A variant of the Clausen numbers A141056, A160014. And of A176591.

Programs

  • Maple
    Clausen := proc(n) local S, i;
    S := numtheory[divisors](n); S := map(i->i+1, S);
    S := select(isprime, S); mul(i, i=S) end:
    A249306 := n -> `if`(n mod 4 = 3, 1, Clausen(n)):
    seq(A249306(n), n=0..59); # Peter Luschny, Nov 10 2014
  • Mathematica
    a[n_] := Denominator[BernoulliB[n]]; a[n_ /; Mod[n, 4] == 1] = 2; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Oct 28 2014 *)

Formula

a(2n) = A002445(n), a(2n+1) = A000034(n+1).

A272383 Numbers n such that Bernoulli number B_{n} has denominator 3318.

Original entry on oeis.org

78, 1014, 2418, 3354, 7566, 8502, 10842, 11622, 12246, 12714, 13026, 15054, 15366, 15522, 16458, 17394, 23946, 26286, 27222, 27534, 29562, 29874, 30342, 31434, 31902, 33774, 34242, 35646, 36114, 40794, 42198, 43602, 44538, 47814, 48126, 48282, 49218, 50154, 52494, 55302, 57174, 57642, 59046, 59982
Offset: 1

Views

Author

Paolo P. Lava, Apr 28 2016

Keywords

Comments

3318 = 2 * 3 * 7 * 79.
All terms are multiples of a(1) = 78.
For these numbers numerator(B_{n}) mod denominator(B_{n}) = 37.

Examples

			Bernoulli B_{78} is 414846365575400828295179035549542073492199375372400483487/3318, hence 78 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q,h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6,3318);
  • Mathematica
    Select[78 Range@ 800, Denominator@ BernoulliB@ # == 3318 &] (* Michael De Vlieger, Apr 28 2016 *)
  • PARI
    lista(nn) = for(n=1, nn, if(denominator(bernfrac(n)) == 3318, print1(n, ", "))); \\ Altug Alkan, Apr 28 2016
    
  • Python
    from sympy import divisors, isprime
    A272383_list = []
    for i in range(78, 10**6, 78):
        for d in divisors(i):
            if d not in (1,2,6,78) and isprime(d+1):
                break
        else:
            A272383_list.append(i) # Chai Wah Wu, May 02 2016

Extensions

a(9)-a(22) from Altug Alkan, Apr 28 2016
More terms from Michael De Vlieger, Apr 28 2016

A295587 Numbers k such that Bernoulli number B_{k} has denominator 13530.

Original entry on oeis.org

40, 6680, 7880, 8920, 9080, 10280, 12520, 12680, 14120, 15320, 15560, 18280, 20840, 21640, 22760, 23480, 25720, 26440, 28040, 30040, 30280, 31880, 33080, 33560, 34520, 35240, 35480, 36280, 38680, 39640, 42040, 43880, 44360, 46120, 46520, 46840, 47240, 47720, 48520
Offset: 1

Views

Author

Paolo P. Lava, Nov 24 2017

Keywords

Comments

13530 = 2*3*5*11*41.
All terms are multiples of a(1) = 40.
For these numbers numerator(B_{k}) mod denominator(B_{k}) = 11519.

Examples

			Bernoulli B_{40} is -261082718496449122051/13530, hence 40 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q, h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6,13530);
    # Alternative: # according to Robert Israel code in A282773
    with(numtheory): filter:= n ->
    select(isprime, map(`+`, divisors(n), 1)) = {2, 3, 5, 11, 41}:
    select(filter, [seq(i, i=1..10^5)]);
  • Mathematica
    Select[Range[50000],Denominator[BernoulliB[#]]==13530&] (* Harvey P. Dale, Jul 29 2025 *)

A295588 Numbers k such that Bernoulli number B_{k} has denominator 14322.

Original entry on oeis.org

30, 1770, 3810, 4170, 4470, 4890, 5910, 5970, 6810, 8070, 9210, 10590, 11370, 11670, 12030, 12990, 13470, 13890, 14370, 14970, 15630, 16890, 17070, 17610, 18510, 18570, 19290, 19410, 20190, 20310, 21270, 22710, 24810, 25710, 26310, 27570, 27870, 29010, 29490, 29730
Offset: 1

Views

Author

Paolo P. Lava, Nov 24 2017

Keywords

Comments

14322 = 2*3*7*11*31.
All terms are multiples of a(1) = 30.
For these numbers numerator(B_{k}) mod denominator(B_{k}) = 12899.

Examples

			Bernoulli B_{30} is 8615841276005/14322, hence 30 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q, h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6,14322);
    # Alternative: # according to Robert Israel code in A282773
    with(numtheory): filter:= n ->
    select(isprime, map(`+`, divisors(n), 1)) = {2, 3, 7, 11, 31}:
    select(filter, [seq(i, i=1..10^5)]);

A295589 Numbers k such that Bernoulli number B_{k} has denominator 33330.

Original entry on oeis.org

100, 1700, 7100, 16700, 22300, 25700, 28300, 31300, 31700, 33100, 35300, 37900, 38300, 38900, 39700, 44900, 45700, 47900, 52100, 56900, 58700, 60700, 66100, 75100, 75700, 78700, 79700, 83900, 85700, 85900, 88100, 90700, 96700, 99100
Offset: 1

Views

Author

Paolo P. Lava, Nov 24 2017

Keywords

Comments

33330= 2*3*5*11*101.
All terms are multiples of a(1) = 100.
For these numbers numerator(B_{k}) mod denominator(B_{k}) = 28859.

Examples

			Bernoulli B_{100} is
-945980378191221252952274330694937218727028415330669361333856962043113954151972 47711/33330, hence 100 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q, h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6, 33330);
    # Alternative: # according to Robert Israel code in A282773
    with(numtheory): filter:= n ->
    select(isprime, map(`+`, divisors(n), 1)) = {2, 3, 5, 11, 101}:
    select(filter, [seq(i, i=1..10^5)]);
  • Mathematica
    Select[Range[100,100000,100],Denominator[BernoulliB[#]]==33330&] (* Harvey P. Dale, Aug 05 2022 *)

A295590 Numbers k such that Bernoulli number B_{k} has denominator 46410.

Original entry on oeis.org

48, 10128, 16944, 21072, 25008, 28176, 31056, 33648, 35184, 39696, 42288, 52656, 55824, 59952, 60432, 62448, 71664, 73104, 77808, 78096, 82704, 83568, 84432, 91824, 93648, 98544, 100176, 100272, 102288, 107664, 108912, 110256, 110832, 112368, 114096, 117168, 120144
Offset: 1

Views

Author

Paolo P. Lava, Nov 24 2017

Keywords

Comments

46410 = 2*3*5*7*13*17.
All terms are multiples of a(1) = 48.
For these numbers numerator(B_{k}) mod denominator(B_{k}) = 31933.

Examples

			46410 = 2*3*5*7*13*17.
Bernoulli B_{48} is -5609403368997817686249127547/46410, hence 48 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q, h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6,64722);
    # Alternative: # according to Robert Israel code in A282773
    with(numtheory): filter:= n ->
    select(isprime, map(`+`, divisors(n), 1)) = {2, 3, 5, 7, 13, 17}:
    select(filter, [seq(i, i=1..10^5)]);
  • Mathematica
    Select[48*Range[2600],Denominator[BernoulliB[#]]==46410&] (* Harvey P. Dale, May 17 2020 *)

A295591 Numbers k such that Bernoulli number B_{k} has denominator 61410.

Original entry on oeis.org

88, 968, 5192, 5368, 13816, 15928, 19624, 19976, 22616, 23144, 23848, 24904, 27368, 27544, 27896, 29656, 31064, 33704, 34936, 38632, 40216, 40568, 40744, 45848, 46024, 48136, 49544, 50248, 51656, 53416, 56584, 56936, 57112, 59048, 60808, 61688, 67672, 68024, 71368
Offset: 1

Views

Author

Paolo P. Lava, Nov 24 2017

Keywords

Comments

61410 = 2*3*5*23*89.
All terms are multiples of a(1) = 88.
For these numbers numerator(B_{k}) mod denominator(B_{k}) = 56003.

Examples

			Bernoulli B_{88} is -1311426488674017507995511424019311843345750275572028644296919890574047/61410 hence 88 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q, h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6, 61410);
    # Alternative: # according to Robert Israel code in A282773
    with(numtheory): filter:= n ->
    select(isprime, map(`+`, divisors(n), 1)) = {2, 3, 5, 23, 89}:
    select(filter, [seq(i, i=1..10^5)]);
  • PARI
    isok(n) = denominator(bernfrac(n)) == 61410; \\ Michel Marcus, Jan 07 2018

A295592 Numbers k such that Bernoulli number B_{k} has denominator 64722.

Original entry on oeis.org

66, 3894, 4686, 5214, 6402, 8382, 9174, 9834, 10362, 10758, 11022, 13134, 14718, 17754, 20262, 20922, 22242, 23034, 23298, 25014, 25278, 25674, 26466, 27786, 28974, 29634, 30162, 31614, 34386, 36102, 37554, 37686, 38742, 39534, 40722, 42438, 44418, 45606, 46266
Offset: 1

Views

Author

Paolo P. Lava, Nov 24 2017

Keywords

Comments

64722 = 2*3*7*23*67.
All terms are multiples of a(1) = 66.
For these numbers numerator(B_{k}) mod denominator(B_{k}) = 62483.

Examples

			Bernoulli B_{66} is
1472600022126335654051619428551932342241899101/64722, hence 66 is in the sequence.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q, h) local n;  for n from 2 by 2 to q do
    if denom(bernoulli(n))=h then print(n); fi; od; end: P(10^6,64722);
    # Alternative: # according to Robert Israel code in A282773
    with(numtheory): filter:= n ->
    select(isprime, map(`+`, divisors(n), 1)) = {2, 3, 7, 23, 67}:
    select(filter, [seq(i, i=1..10^5)]);
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