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.

User: Oleg P. Kirillov

Oleg P. Kirillov's wiki page.

Oleg P. Kirillov has authored 7 sequences.

A235933 Numbers coprime to 35.

Original entry on oeis.org

1, 2, 3, 4, 6, 8, 9, 11, 12, 13, 16, 17, 18, 19, 22, 23, 24, 26, 27, 29, 31, 32, 33, 34, 36, 37, 38, 39, 41, 43, 44, 46, 47, 48, 51, 52, 53, 54, 57, 58, 59, 61, 62, 64, 66, 67, 68, 69, 71, 72, 73, 74, 76, 78, 79, 81, 82, 83, 86, 87, 88, 89, 92, 93, 94, 96, 97, 99
Offset: 1

Author

Oleg P. Kirillov, Jan 17 2014

Keywords

Comments

The asymptotic density of this sequence is 24/35. - Amiram Eldar, Oct 23 2020

Crossrefs

Cf. A160547 (numbers coprime to 31), A229968 (numbers coprime to 33), A204458 (numbers coprime to 34), A007310 (numbers coprime to 36).
Cf. A045572 (numbers not divisible by 5 or 2), A229829 (numbers not divisible by 5 or 3), A047201 (numbers not divisible by 5), A236207 (numbers not divisible by 5 or 11).

Programs

  • Haskell
    a235933 n = a235933_list !! (n-1)
    a235933_list = filter ((== 1) . gcd 35) [1..]
    -- Reinhard Zumkeller, Mar 27 2014
  • Magma
    [n: n in [1..100] | GCD(n,35) eq 1]; // Bruno Berselli, Mar 27 2014
    
  • Mathematica
    Select[Range[100], GCD[#, 35] == 1 &] (* Bruno Berselli, Mar 27 2014 *)
  • Sage
    [i for i in range(100) if gcd(i, 35) == 1] # Bruno Berselli, Mar 27 2014
    

Extensions

Signature corrected from Georg Fischer, Feb 07 2021
Erroneous recurrence removed from Bruno Berselli, Feb 08 2021

A236204 Numbers not divisible by 2, 3 or 11.

Original entry on oeis.org

1, 5, 7, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, 43, 47, 49, 53, 59, 61, 65, 67, 71, 73, 79, 83, 85, 89, 91, 95, 97, 101, 103, 107, 109, 113, 115, 119, 125, 127, 131, 133, 137, 139, 145, 149, 151, 155, 157, 161, 163, 167, 169, 173, 175, 179, 181, 185, 191, 193, 197, 199, 203, 205
Offset: 1

Author

Oleg P. Kirillov, Jan 20 2014

Keywords

Comments

All primes except 2, 3 and 11 are in this sequence. Any product of terms is also a term in the sequence. - Alonso del Arte, Feb 04 2014
Also integers n such that least prime factor of 32^n-1 is 31. - Giovanni Resta, Mar 22 2014
Numbers coprime to 66. The asymptotic density of this sequence is 10/33. - Amiram Eldar, Oct 23 2020

Crossrefs

Cf. A235583.

Programs

Formula

a(n) = a(n-1) + a(n-20) - a(n-21). - Charles R Greathouse IV, Mar 26 2014
For n > 20, a(n) = a(n - 20) + 66. - Zak Seidov, Mar 27 2014
G.f.: x*(x^20 + 4*x^19 + 2*x^18 + 6*x^17 + 4*x^16 + 2*x^15 + 4*x^14 + 2*x^13 + 4*x^12 + 2*x^11 + 4*x^10 + 2*x^9 + 4*x^8 + 2*x^7 + 4*x^6 + 2*x^5 + 4*x^4 + 6*x^3 + 2*x^2 + 4*x + 1)/(x^21 - x^20 - x + 1). - Chai Wah Wu, Aug 03 2020

A236207 Numbers not divisible by 5 or 11.

Original entry on oeis.org

1, 2, 3, 4, 6, 7, 8, 9, 12, 13, 14, 16, 17, 18, 19, 21, 23, 24, 26, 27, 28, 29, 31, 32, 34, 36, 37, 38, 39, 41, 42, 43, 46, 47, 48, 49, 51, 52, 53, 54, 56, 57, 58, 59, 61, 62, 63, 64, 67, 68, 69, 71, 72, 73, 74, 76, 78, 79, 81, 82, 83, 84, 86, 87, 89, 91, 92, 93, 94, 96, 97
Offset: 1

Author

Oleg P. Kirillov, Jan 20 2014

Keywords

Crossrefs

Intersection of A047201 and A160542.

Programs

  • Mathematica
    Select[Range[100], Mod[#, 5] > 0 && Mod[#, 11] > 0 &] (* or *) Select[Range[100], Or @@ Divisible[#, {5, 11}] == False &] (* Bruno Berselli, Mar 24 2014 *)

A236217 Numbers not divisible by 3, 5 or 11.

Original entry on oeis.org

1, 2, 4, 7, 8, 13, 14, 16, 17, 19, 23, 26, 28, 29, 31, 32, 34, 37, 38, 41, 43, 46, 47, 49, 52, 53, 56, 58, 59, 61, 62, 64, 67, 68, 71, 73, 74, 76, 79, 82, 83, 86, 89, 91, 92, 94, 97, 98, 101, 103, 104, 106, 107, 109, 112, 113, 116, 118, 119, 122, 124, 127, 128
Offset: 1

Author

Oleg P. Kirillov, Jan 20 2014

Keywords

Comments

Numbers coprime to 165. The asymptotic density of this sequence is 16/33. - Amiram Eldar, Oct 23 2020

Crossrefs

Intersection of: A160542 and A229829; A047201 and A229968; A001651, A047201 and A160542.

Programs

  • Mathematica
    Select[Range[200], Mod[#, 3] > 0 && Mod[#, 5] > 0 && Mod[#, 11] > 0 &] (* or *) Select[Range[200], Or @@ Divisible[#, {3, 5, 11}] == False &] (* Bruno Berselli, Mar 24 2014 *)
    Select[Range[130], CoprimeQ[165, #] &] (* Amiram Eldar, Oct 23 2020 *)

Formula

a(n) = a(n-1) + a(n-80) - a(n-81) for n > 81. - Bruno Berselli, Mar 25 2014

A236208 Numbers not divisible by 2, 5 or 11.

Original entry on oeis.org

1, 3, 7, 9, 13, 17, 19, 21, 23, 27, 29, 31, 37, 39, 41, 43, 47, 49, 51, 53, 57, 59, 61, 63, 67, 69, 71, 73, 79, 81, 83, 87, 89, 91, 93, 97, 101, 103, 107, 109, 111, 113, 117, 119, 123, 127, 129, 131, 133, 137, 139, 141, 147, 149, 151, 153, 157, 159, 161, 163
Offset: 1

Author

Oleg P. Kirillov, Jan 20 2014

Keywords

Comments

Numbers coprime to 110. The asymptotic density of this sequence is 4/11. - Amiram Eldar, Oct 23 2020

Crossrefs

Programs

  • Mathematica
    Select[Range[200], CoprimeQ[110, #] &] (* Amiram Eldar, Oct 23 2020 *)

Formula

G.f.: (x^36 +x^35 +2*x^34 -2*x^33 +2*x^32 +x^31 -x^30 +2*x^29 -2*x^28 +4*x^27 -x^26 -x^25 +6*x^24 -6*x^23 +4*x^22 -x^21 +x^20 +4*x^19 -6*x^18 +4*x^17 +x^16 -x^15 +4*x^14 -6*x^13 +6*x^12 -x^11 -x^10 +4*x^9 -2*x^8 +2*x^7 -x^6 +x^5 +2*x^4 -2*x^3 +2*x^2 +x +1)*x / ((x+1) *(x^2+1) *(x^4-x^3+x^2-x+1) *(x^4+1) *(x^8-x^6+x^4-x^2+1) *(x^16-x^12+x^8-x^4+1) *(x-1)^2). - Alois P. Heinz, Feb 13 2014

A236206 Numbers not divisible by 3, 5 or 7.

Original entry on oeis.org

1, 2, 4, 8, 11, 13, 16, 17, 19, 22, 23, 26, 29, 31, 32, 34, 37, 38, 41, 43, 44, 46, 47, 52, 53, 58, 59, 61, 62, 64, 67, 68, 71, 73, 74, 76, 79, 82, 83, 86, 88, 89, 92, 94, 97, 101, 103, 104, 106, 107, 109, 113, 116, 118, 121, 122, 124, 127, 128, 131, 134, 136
Offset: 1

Author

Oleg P. Kirillov, Jan 20 2014

Keywords

Comments

Numbers whose odd part is 11-rough: products of terms of A008364 and powers of 2 (terms of A000079). - Peter Munn, Aug 03 2020
Numbers coprime to 105. The asymptotic density of this sequence is 16/35. - Amiram Eldar, Oct 23 2020

Crossrefs

Subsequences: A000079, A008364.
Intersection of any 2 of A160545, A229829, A235933.
Other sequences with similar definitions: A007775, A236217.

Programs

  • Mathematica
    Select[Range[300], Mod[#, 3] > 0 && Mod[#, 5] > 0 && Mod[#, 7] > 0 &] (* T. D. Noe, Feb 05 2014 *)
    Select[Range[300],Or@@Divisible[#,{3,5,7}]==False&] (* Harvey P. Dale, Mar 13 2014 *)
    Select[Range[150], CoprimeQ[105, #] &] (* Amiram Eldar, Oct 23 2020 *)

Formula

a(n) = a(n-1) + a(n-48) - a(n-49). - Amiram Eldar, Oct 23 2020

A235583 Numbers not divisible by 2, 5 or 7.

Original entry on oeis.org

1, 3, 9, 11, 13, 17, 19, 23, 27, 29, 31, 33, 37, 39, 41, 43, 47, 51, 53, 57, 59, 61, 67, 69, 71, 73, 79, 81, 83, 87, 89, 93, 97, 99, 101, 103, 107, 109, 111, 113, 117, 121, 123, 127, 129, 131, 137, 139, 141, 143, 149, 151, 153, 157, 159, 163, 167, 169, 171, 173, 177, 179, 181, 183
Offset: 1

Author

Oleg P. Kirillov, Jan 12 2014

Keywords

Comments

All primes, except 2, 5 and 7, are in this sequence. Any product of terms is also a term in the sequence. For example, a(2)a(4) = 3 * 11 = 33 = a(12). - Alonso del Arte, Jan 12 2014
In other words, numbers equivalent 1,3,9,...,69 modulo 70. This means the first differences of the sequence are 24-periodic. - Ralf Stephan, Jan 14 2014
Numbers coprime to 70. The asymptotic density of this sequence is 12/35. - Amiram Eldar, Oct 23 2020

Examples

			51 = 3 * 17, and gcd(51, 70) = 1, so it is in the sequence.
53 is prime, so it is in the sequence.
55 = 5 * 11, and gcd(55, 70) = 5, so it is not in the sequence.
		

Crossrefs

Cf. A007775, A008364 (subsequence).

Programs

  • Mathematica
    Select[Range[210], GCD[#, 70] == 1 &] (* Alonso del Arte, Jan 12 2014 *)
    Select[Range[300], Mod[#, 2]>0 &&Mod[#, 5]>0 &&Mod[#, 7]>0&] (* Vincenzo Librandi, Feb 08 2014 *)

Formula

G.f.: x*(x^22 +3*x^21 +8*x^20 +7*x^19 +x^18-2*x^17 -x^16 +5*x^15 +10*x^14 +7*x^13 -x^12 -6*x^11 -x^10 +7*x^9 +10*x^8 +5*x^7 -x^6 -2*x^5 +x^4 +7*x^3 +8*x^2 +3*x +1) / ((x+1) *(x^2+1) *(x^2+x+1) *(x^4-x^2+1) *(x^4+1) *(x^8-x^4+1) *(x-1)^2). - Alois P. Heinz, Jan 12 2014