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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A293443 Multiplicative with a(p^e) = A019565(A193231(e)).

Original entry on oeis.org

1, 2, 2, 6, 2, 4, 2, 3, 6, 4, 2, 12, 2, 4, 4, 10, 2, 12, 2, 12, 4, 4, 2, 6, 6, 4, 3, 12, 2, 8, 2, 5, 4, 4, 4, 36, 2, 4, 4, 6, 2, 8, 2, 12, 12, 4, 2, 20, 6, 12, 4, 12, 2, 6, 4, 6, 4, 4, 2, 24, 2, 4, 12, 15, 4, 8, 2, 12, 4, 8, 2, 18, 2, 4, 12, 12, 4, 8, 2, 20, 10, 4, 2, 24, 4, 4, 4, 6, 2, 24, 4, 12, 4, 4, 4, 10, 2, 12, 12, 36, 2, 8, 2, 6, 8
Offset: 1

Views

Author

Antti Karttunen, Oct 31 2017

Keywords

Crossrefs

Programs

Formula

a(1) = 1; for n > 1, a(n) = A019565(A193231(A067029(n))) * a(A028234(n)).
For all n >= 1, A007814(a(n)) = A293439(n).
For all k in A270428, A007814(a(k)) = A001221(k).

A366263 Doudna sequence permuted by Blue code: a(n) = A005940(1+A193231(n)).

Original entry on oeis.org

1, 2, 4, 3, 6, 5, 9, 8, 16, 27, 25, 18, 15, 12, 10, 7, 14, 11, 21, 20, 35, 30, 24, 45, 81, 32, 54, 125, 36, 75, 49, 50, 100, 147, 121, 98, 225, 72, 150, 245, 625, 162, 64, 243, 250, 343, 375, 108, 33, 28, 22, 13, 40, 63, 55, 42, 90, 175, 135, 48, 77, 70, 60, 105, 210, 385, 315, 120, 143, 154, 140, 231, 525, 180
Offset: 0

Views

Author

Antti Karttunen, Oct 06 2023

Keywords

Crossrefs

Programs

  • PARI
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A193231(n) = { my(x='x); subst(lift(Mod(1, 2)*subst(Pol(binary(n), x), x, 1+x)), x, 2) };
    A366263(n) = A005940(1+A193231(n));

Formula

a(n) = A332450(A005940(1+n)).
For all n >= 0, A001222(a(n)) = A234022(n) and A046523(a(n)) = A286601(n).
For all n >= 1, A055396(a(n)) = A277818(n) = 1+A268389(n).

A234024 Self-inverse permutation of nonnegative integers, A059893-conjugate of blue code: a(n) = A059893(A193231(A059893(n))).

Original entry on oeis.org

0, 1, 3, 2, 6, 5, 4, 7, 15, 10, 9, 12, 11, 14, 13, 8, 24, 23, 18, 29, 20, 27, 30, 17, 16, 31, 26, 21, 28, 19, 22, 25, 57, 40, 39, 54, 45, 60, 51, 34, 33, 48, 63, 46, 53, 36, 43, 58, 41, 56, 55, 38, 61, 44, 35, 50, 49, 32, 47, 62, 37, 52, 59, 42, 106, 89, 72, 123
Offset: 0

Views

Author

Antti Karttunen, Dec 28 2013

Keywords

Crossrefs

Programs

Formula

a(n) = A059893(A193231(A059893(n))).
a(n) = A059894(A234027(A059894(n))).

A234026 Permutation of nonnegative integers: a(n) = A193231(A054429(n)).

Original entry on oeis.org

0, 1, 2, 3, 7, 6, 4, 5, 8, 9, 11, 10, 13, 12, 14, 15, 25, 24, 26, 27, 28, 29, 31, 30, 22, 23, 21, 20, 19, 18, 16, 17, 42, 43, 41, 40, 47, 46, 44, 45, 37, 36, 38, 39, 32, 33, 35, 34, 59, 58, 56, 57, 62, 63, 61, 60, 52, 53, 55, 54, 49, 48, 50, 51, 127, 126, 124
Offset: 0

Views

Author

Antti Karttunen, Dec 28 2013

Keywords

Crossrefs

Inverse permutation: A234025. Cf. A234024.

Programs

Formula

a(n) = A193231(A054429(n)).
a(n) = A054429(A234027(n)).

A245454 Self-inverse permutation of nonnegative integers, A075158-conjugate of blue code: a(n) = 1 + A075157(A193231(A075158(n-1))).

Original entry on oeis.org

1, 2, 4, 3, 6, 5, 18, 8, 9, 25, 11, 16, 64, 14, 27, 12, 96, 7, 288, 21, 20, 243, 891, 45, 10, 405, 15, 162, 33750, 30, 78650, 75, 625, 2025, 35, 81, 390390, 224, 875, 250, 41, 375, 16384, 270, 24, 300125, 24576, 150, 125, 54, 6125, 1350, 73728, 50, 108, 350, 594, 140777, 5845851, 98, 221433750, 1446445, 343, 13
Offset: 1

Views

Author

Antti Karttunen, Jul 22 2014

Keywords

Crossrefs

Programs

Formula

a(n) = 1 + A075157(A193231(A075158(n-1))).

A280501 "Blue kernel" of n: a(n) = A091255(n, A193231(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 6, 7, 1, 7, 6, 1, 6, 1, 7, 1, 1, 1, 18, 19, 20, 21, 1, 1, 6, 1, 1, 7, 7, 1, 6, 1, 1, 1, 6, 7, 18, 1, 19, 1, 20, 1, 21, 1, 1, 7, 6, 1, 6, 7, 1, 1, 1, 19, 18, 1, 7, 1, 6, 1, 20, 1, 1, 21, 1, 21, 6, 1, 20, 1, 7, 1, 18, 1, 1, 1, 19, 1, 6, 7, 20, 1, 1, 7, 21, 1, 6, 1, 1, 1, 18, 1, 6, 7, 1, 19, 6, 1, 7, 1, 1, 7, 6, 1, 1, 1, 106, 107, 108, 109, 1, 1, 7
Offset: 1

Views

Author

Antti Karttunen, Jan 09 2017

Keywords

Crossrefs

Programs

Formula

a(n) = A091255(n, A193231(n)).
Other identities. For all n >= 1:
a(A193231(n)) = a(n).
A048720(a(n), A280502(n)) = n.

A332450 Self-inverse permutation of natural numbers, "Blue code" conjugated by A156552 and its inverse: a(n) = A005940(1+A193231(A156552(n))).

Original entry on oeis.org

1, 2, 4, 3, 6, 5, 16, 8, 9, 27, 14, 18, 100, 11, 25, 7, 210, 12, 256, 20, 21, 147, 38, 45, 15, 385, 10, 98, 1156, 30, 1938, 50, 121, 2187, 35, 125, 234256, 23, 315, 245, 6902, 72, 3496900, 120, 24, 1083, 9699690, 108, 81, 32, 15625, 1458, 65536, 75, 225, 231, 57, 2185, 106, 243, 8836, 771147, 150, 105, 143, 154, 14946, 68, 529, 162
Offset: 1

Views

Author

Antti Karttunen, Feb 15 2020

Keywords

Crossrefs

Cf. A293448 (A057889 similarly conjugated).

Programs

  • PARI
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ From A005940
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A193231(n) = { my(x='x); subst(lift(Mod(1, 2)*subst(Pol(binary(n), x), x, 1+x)), x, 2) }; \\ From A193231
    A332450(n) = A005940(1+A193231(A156552(n)));

Formula

a(n) = A005940(1+A193231(A156552(n))).
a(A003961(n)) = A332451(a(n)); a(A332451(n)) = A003961(a(n)).
a(n) = A366263(A156552(n)). - Antti Karttunen, Oct 06 2023

A369043 LCM-transform of Blue code (A193231).

Original entry on oeis.org

1, 3, 2, 5, 2, 1, 7, 1, 1, 1, 13, 1, 11, 3, 2, 17, 2, 1, 19, 1, 1, 23, 1, 1, 31, 29, 1, 3, 1, 1, 5, 1, 1, 1, 7, 1, 1, 53, 1, 1, 61, 1, 1, 1, 1, 1, 59, 1, 1, 1, 2, 1, 1, 1, 37, 1, 1, 1, 47, 1, 41, 43, 1, 1, 1, 1, 1, 1, 3, 83, 1, 1, 1, 89, 1, 1, 1, 1, 1, 1, 1, 71, 1, 1, 2, 1, 67, 1, 1, 1, 73, 1, 79, 1, 1, 1, 103, 101
Offset: 1

Views

Author

Antti Karttunen, Jan 12 2024

Keywords

Comments

Blue code, A193231, is a self-inverse permutation related to the binary expansion of n that keeps all the numbers of range [2^k, 2^(1+k)[ in the same range, i.e., for all n >= 1, A000523(A193231(n)) = A000523(n), from which it immediately follows that A193231 has the property S mentioned in the comments of A368900, and therefore this sequence is equal to A014963(A193231(n)), for n >= 1.

Crossrefs

Programs

  • PARI
    up_to = 65537; \\ Checked up to 2^17;
    LCMtransform(v) = { my(len = length(v), b = vector(len), g = vector(len)); b[1] = g[1] = 1; for(n=2,len, g[n] = lcm(g[n-1],v[n]); b[n] = g[n]/g[n-1]); (b); };
    A193231(n) = { my(x='x); subst(lift(Mod(1, 2)*subst(Pol(binary(n), x), x, 1+x)), x, 2) };
    v369043 = LCMtransform(vector(up_to,i,A193231(i)));
    A369043(n) = v369043[n];
    A014963(n) = { ispower(n, , &n); if(isprime(n), n, 1); };

Formula

a(n) = lcm {1..A193231(n)} / lcm {1..A193231(n-1)}.
a(n) = A014963(A193231(n)). [See comments.]
For n >= 1, Product_{d|n} a(A193231(d)) = n. [Implied by above.]

A234751 Self-inverse permutation of integers induced by the restriction of blue-code to irreducible polynomials over GF(2): a(n) = A091227(A193231(A014580(n))).

Original entry on oeis.org

2, 1, 3, 5, 4, 6, 8, 7, 12, 14, 13, 9, 11, 10, 17, 18, 15, 16, 20, 19, 21, 23, 22, 41, 39, 40, 38, 37, 34, 33, 35, 36, 30, 29, 31, 32, 28, 27, 25, 26, 24, 43, 42, 47, 46, 45, 44, 49, 48, 51, 50, 52, 54, 53, 55, 71, 69, 70, 68, 65, 64, 67, 66, 61, 60, 63, 62, 59, 57, 58, 56
Offset: 1

Views

Author

Antti Karttunen, Feb 12 2014

Keywords

Comments

This permutation is also induced when A234747 is restricted to primes: a(n) = A000720(A234747(A000040(n))) because of the way A234747 has been defined.
Note that each subsequence a(1)..a(A062692(j)) is closed (i.e., no cycles are leaking out) because blue code (A193231) preserves the degree of polynomials over GF(2) it operates upon.

Crossrefs

Programs

Formula

A244987 Self-inverse permutation of natural numbers, A245703-conjugate of Blue code: a(n) = A245704(A193231(A245703(n))).

Original entry on oeis.org

1, 3, 2, 6, 5, 4, 13, 8, 21, 15, 23, 16, 7, 25, 10, 12, 41, 18, 19, 64, 9, 22, 11, 49, 14, 26, 77, 39, 37, 34, 263, 105, 38, 30, 88, 70, 29, 33, 28, 133, 17, 54, 73, 126, 51, 462, 53, 60, 24, 66, 45, 74, 47, 42, 78, 94, 156, 81, 239, 48, 97, 62, 100, 20, 155, 50, 79, 98, 84, 36, 167, 141, 43, 52, 129, 164, 27, 55
Offset: 1

Views

Author

Antti Karttunen, Aug 07 2014

Keywords

Crossrefs

Programs

Formula

a(n) = A245704(A193231(A245703(n))).
Other identities. For all n >= 1, the following holds:
A010051(a(n)) = A010051(n). [Maps primes to primes and composites to composites].
Previous Showing 11-20 of 85 results. Next