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 1-10 of 23 results. Next

A365462 a(n) = A356867(n) - n.

Original entry on oeis.org

0, 0, 0, 1, -1, 0, 3, 0, 0, -3, 3, 3, 12, 6, -3, 34, -1, 0, 16, 8, 9, 103, 17, 0, 75, 6, 0, -17, -7, -9, 24, 12, 9, 36, 21, 9, 12, 60, 36, 135, 99, 18, 207, 36, -9, 199, 149, 102, 576, 150, -3, 448, 11, 0, 22, 54, 48, 217, 29, 24, 289, 50, 27, 279, 425, 309, 808, 212, 51, 1180, 89, 0, 1152, 318, 225, 3049, 323, 18
Offset: 1

Views

Author

Antti Karttunen, Sep 15 2023

Keywords

Crossrefs

Cf. A356867, A364958 (positions of 0's), A365463.
Cf. also A364499.

Programs

  • PARI
    up_to = 19683;
    A356867list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); (v); };
    v356867 = A356867list(up_to);
    A356867(n) = v356867[n];
    A365462(n) = (A356867(n)-n);

A365463 a(n) = gcd(n, A356867(n)), where A356867 is Sycamore's Doudna variant D(3).

Original entry on oeis.org

1, 2, 3, 1, 1, 6, 1, 8, 9, 1, 1, 3, 1, 2, 3, 2, 1, 18, 1, 4, 3, 1, 1, 24, 25, 2, 27, 1, 1, 3, 1, 4, 3, 2, 7, 9, 1, 2, 3, 5, 1, 6, 1, 4, 9, 1, 1, 6, 1, 50, 3, 4, 1, 54, 11, 2, 3, 1, 1, 12, 1, 2, 9, 1, 5, 3, 1, 4, 3, 10, 1, 72, 1, 2, 75, 1, 1, 6, 1, 16, 81, 1, 1, 3, 5, 2, 3, 2, 1, 9, 91, 2, 3, 1, 5, 12, 1, 2, 9, 5, 1, 6, 1, 8, 21
Offset: 1

Views

Author

Antti Karttunen, Sep 15 2023

Keywords

Crossrefs

Cf. A007949, A356867, A364957 (Dirichlet inverse), A365462, A365464, A365465.
Cf. also A364500.

Programs

  • PARI
    up_to = 19683;
    A356867list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); (v); };
    v356867 = A356867list(up_to);
    A356867(n) = v356867[n];
    A365463(n) = gcd(n, A356867(n));

Formula

a(n) = gcd(n, A365462(n)) = gcd(A356867(n), A365462(n)).
a(n) = n / A365464(n) = A356867(n) / A365465(n).
For all n >= 1, A007949(a(n)) = A007949(n), A011655(a(n)) = A011655(n).

A365719 The least number with the same prime signature as A356867(1+n), where A356867 is Sycamore's Doudna variant D(3).

Original entry on oeis.org

1, 2, 2, 2, 4, 6, 6, 8, 4, 2, 6, 6, 4, 12, 12, 12, 16, 12, 6, 12, 30, 8, 24, 24, 36, 32, 8, 2, 6, 6, 6, 12, 30, 30, 24, 12, 4, 12, 12, 12, 60, 60, 24, 48, 36, 12, 36, 60, 16, 72, 48, 72, 64, 24, 6, 30, 30, 12, 24, 60, 60, 48, 60, 8, 60, 24, 24, 120, 120, 48, 96, 72, 36, 72, 180, 32, 144, 96, 216, 128, 16, 2, 6, 6, 6, 12
Offset: 0

Views

Author

Antti Karttunen, Sep 17 2023

Keywords

Crossrefs

Cf. A046523, A356867, A365720 (rgs-transform), A365721, A365722.
Cf. also A278222.

Programs

Formula

a(n) = A046523(A356867(1+n)).

A365721 The number of distinct prime factors in A356867(1+n), where A356867 is Sycamore's Doudna variant D(3).

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 3, 1, 2, 2, 2, 1, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 1, 2, 2, 2, 3, 3, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 1, 2, 2, 3, 3, 2, 2, 3, 3, 2, 3, 1, 3, 2, 2, 3, 3, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 1, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 4, 2, 3, 3, 3
Offset: 0

Views

Author

Antti Karttunen, Sep 17 2023

Keywords

Crossrefs

Programs

Formula

a(n) = A001221(A356867(1+n)) = A001221(A365719(n)).
a(n) <= A365722(n).

A365722 The number of prime factors (with multiplicity) in A356867(1+n), where A356867 is Sycamore's Doudna variant D(3).

Original entry on oeis.org

0, 1, 1, 1, 2, 2, 2, 3, 2, 1, 2, 2, 2, 3, 3, 3, 4, 3, 2, 3, 3, 3, 4, 4, 4, 5, 3, 1, 2, 2, 2, 3, 3, 3, 4, 3, 2, 3, 3, 3, 4, 4, 4, 5, 4, 3, 4, 4, 4, 5, 5, 5, 6, 4, 2, 3, 3, 3, 4, 4, 4, 5, 4, 3, 4, 4, 4, 5, 5, 5, 6, 5, 4, 5, 5, 5, 6, 6, 6, 7, 4, 1, 2, 2, 2, 3, 3, 3, 4, 3, 2, 3, 3, 3, 4, 4, 4, 5, 4, 3, 4, 4, 4, 5, 5, 5
Offset: 0

Views

Author

Antti Karttunen, Sep 17 2023

Keywords

Comments

Sum of digits minus the number of trailing 2's in the base-3 representation of n (A007089).

Crossrefs

Programs

Formula

a(n) = A001222(A356867(1+n)) = A001222(A365719(n)).
a(n) = A053735(n) - A007949(1+n).
a(n) >= A365721(n).

A365465 a(n) = A356867(n) / gcd(n, A356867(n)).

Original entry on oeis.org

1, 1, 1, 5, 4, 1, 10, 1, 1, 7, 14, 5, 25, 10, 4, 25, 16, 1, 35, 7, 10, 125, 40, 1, 4, 16, 1, 11, 22, 7, 55, 11, 14, 35, 8, 5, 49, 49, 25, 35, 140, 10, 250, 20, 4, 245, 196, 25, 625, 4, 16, 125, 64, 1, 7, 55, 35, 275, 88, 7, 350, 56, 10, 343, 98, 125, 875, 70, 40, 125, 160, 1, 1225, 196, 4, 3125, 400, 16, 1000, 8, 1, 13, 26
Offset: 1

Views

Author

Antti Karttunen, Sep 15 2023

Keywords

Comments

Denominator of n / A356867(n).

Crossrefs

Cf. A356867, A365462, A365463, A365464 (numerators).
Cf. also A364502.

Programs

  • PARI
    up_to = 19683;
    A356867list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); (v); };
    v356867 = A356867list(up_to);
    A356867(n) = v356867[n];
    A365465(n) = (A356867(n)/gcd(n, A356867(n)));

Formula

a(n) = A356867(n) / A365463(n).

A365718 Lexicographically earliest infinite sequence such that a(i) = a(j) => A365717(i) = A365717(j) for all i, j >= 0, where A365717(n) = A348717(A356867(1+n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Sep 17 2023

Keywords

Comments

Restricted growth sequence transform of A365717.
For all i, j >= 0: a(i) = a(j) => A365720(i) = A365720(j).
In contrast to austere A103391, which is easily computed from n's binary expansion, the scatter plot here with its slender seaweed-like branchings suggests that this sequence is not just a simple derivation of base-3 expansion of n.

Crossrefs

Cf. also A103391 (similar transformation applied to A005940) and A365715 (compare the scatter plot).

Programs

  • PARI
    up_to = 59049; \\ = 3^10.
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A348717(n) = if(1==n, 1, my(f = factor(n), k = primepi(f[1, 1])-1); for (i=1, #f~, f[i, 1] = prime(primepi(f[i, 1])-k)); factorback(f));
    A356867list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); (v); };
    v365718 = rgs_transform(apply(A348717,A356867list(1+up_to)));
    A365718(n) = v365718[1+n];

A365390 Inverse permutation of A356867, where A356867 is Sycamore's Doudna variant D(3).

Original entry on oeis.org

1, 2, 3, 5, 4, 6, 10, 8, 9, 7, 28, 15, 82, 11, 12, 17, 244, 18, 730, 14, 30, 29, 2188, 24, 13, 83, 27, 20, 6562, 21, 19684, 26, 84, 245, 19, 45, 59050, 731, 246, 23, 177148, 33, 531442, 32, 36, 2189, 1594324, 51, 37, 16, 732, 86, 4782970, 54, 31, 35, 2190, 6563, 14348908, 42, 43046722, 19685, 90, 53, 85, 87, 129140164
Offset: 1

Views

Author

Antti Karttunen, Sep 15 2023

Keywords

Crossrefs

Cf. A365389 (one less), A356867 (inverse), A364958 (fixed points).
Cf. also A005941.

Programs

  • PARI
    up_to = 1+(3^15);
    A365390list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); my(invs=List([]),x); for(i=1,oo,if(mapisdefined(met,i,&x), listput(invs,x), if(isprime(i)&&i>4, listput(invs, 1+(3^(primepi(i)-2))), return(Vec(invs))))); };
    v365390 = A365390list(up_to);
    A365390(n) = v365390[n];
    for(n=1,#v365390,print1(A365390(n),", "));
    
  • PARI
    See Links section.

Formula

For all n >= 1, A356867(a(n)) = n.

A365464 a(n) = n / gcd(n, A356867(n)).

Original entry on oeis.org

1, 1, 1, 4, 5, 1, 7, 1, 1, 10, 11, 4, 13, 7, 5, 8, 17, 1, 19, 5, 7, 22, 23, 1, 1, 13, 1, 28, 29, 10, 31, 8, 11, 17, 5, 4, 37, 19, 13, 8, 41, 7, 43, 11, 5, 46, 47, 8, 49, 1, 17, 13, 53, 1, 5, 28, 19, 58, 59, 5, 61, 31, 7, 64, 13, 22, 67, 17, 23, 7, 71, 1, 73, 37, 1, 76, 77, 13, 79, 5, 1, 82, 83, 28, 17, 43, 29, 44, 89, 10
Offset: 1

Views

Author

Antti Karttunen, Sep 15 2023

Keywords

Comments

Numerator of n / A356867(n).

Crossrefs

Cf. A356867, A365462, A365463, A365465 (denominators).
Cf. also A364501.

Programs

  • PARI
    up_to = 19683;
    A356867list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); (v); };
    v356867 = A356867list(up_to);
    A356867(n) = v356867[n];
    A365464(n) = n/gcd(n, A356867(n));

Formula

a(n) = n / A365463(n).

A364958 Fixed points of A356867, where A356867 is Sycamore's Doudna variant D(3).

Original entry on oeis.org

1, 2, 3, 6, 8, 9, 18, 24, 27, 54, 72, 81, 91, 162, 216, 243, 273, 486, 648, 729, 819, 1458, 1944, 2187, 2457, 4374, 5832, 6561, 7371, 13122, 17496, 19683, 22113, 39366, 52488, 59049, 66339, 118098, 157464, 177147, 199017, 354294, 472392, 531441, 597051, 1062882, 1417176, 1594323, 1791153, 3188646, 4251528, 4782969
Offset: 1

Views

Author

Keywords

Comments

Conjecture: All terms are of the form k*3^n, where k = 1,2,8,91, and n >= 0. - David James Sycamore, Aug 16 2023

Crossrefs

Fixed points of A356867 and of A365390, positions of 0's in A365462.

Programs

  • Mathematica
    Block[{a, c, i, j, k, m, p, t, nn},
      nn = 3^12; m = 1; i = 2; p = Prime[i]; c[_] = False;
      Monitor[Reap[Do[Set[{m, k}, {1, n - p^Floor[Log[p, n]]}];
        If[k == 0, Sow[n]; Set[{a[n], c[n]}, {n, True}],
          While[Set[t, Prime[m] a[k]]; Or[m == i, c[t]], m++];
          If[t == n, Sow[n]]; Set[{a[n], c[t]}, {t, True}] ],
    {n, nn}] ][[-1, 1]], n] ] (* Michael De Vlieger, Jul 02 2025 *)
  • PARI
    up_to = 3^14;
    A356867list(up_to) = { my(v=vector(up_to),met=Map(),h=0,ak); for(i=1,#v,if(1==vecsum(digits(i,3)), v[i] = i; h = i, ak = v[i-h]; forprime(p=2,,if(3!=p && !mapisdefined(met,p*ak), v[i] = p*ak; break))); mapput(met,v[i],i)); (v); };
    v356867 = A356867list(up_to);
    A356867(n) = v356867[n];
    isA364958(n) = (A356867(n)==n);

Formula

{k | k==A356867(k)}.
Showing 1-10 of 23 results. Next