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 1-3 of 3 results.

A344026 Arithmetic derivative applied to the Doudna sequence: a(n) = A003415(A005940(1+n)).

Original entry on oeis.org

0, 1, 1, 4, 1, 5, 6, 12, 1, 7, 8, 16, 10, 21, 27, 32, 1, 9, 10, 24, 12, 31, 39, 44, 14, 45, 55, 60, 75, 81, 108, 80, 1, 13, 14, 32, 16, 41, 51, 68, 18, 59, 71, 92, 95, 123, 162, 112, 22, 77, 91, 140, 119, 185, 240, 156, 147, 275, 350, 216, 500, 297, 405, 192, 1, 15, 16, 48, 18, 61, 75, 92, 20, 87, 103, 124, 135, 165, 216
Offset: 0

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Author

Antti Karttunen, May 07 2021

Keywords

Comments

Coincides with A344028 on Fibbinary numbers, A003714.

Crossrefs

Cf. A000079 (positions of ones), A003415, A003714, A005940.
Cf. also A344027, A344028, A344182.

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
    A344026(n) = A003415(A005940(1+n));

Formula

a(2^n) = 1 for all n >= 0.

A344028 a(n) = A069359(A005940(1+n)).

Original entry on oeis.org

0, 1, 1, 2, 1, 5, 3, 4, 1, 7, 8, 10, 5, 15, 9, 8, 1, 9, 10, 14, 12, 31, 24, 20, 7, 35, 40, 30, 25, 45, 27, 16, 1, 13, 14, 18, 16, 41, 30, 28, 18, 59, 71, 62, 60, 93, 72, 40, 11, 63, 70, 70, 84, 155, 120, 60, 49, 175, 200, 90, 125, 135, 81, 32, 1, 15, 16, 26, 18, 61, 42, 36, 20, 87, 103, 82, 80, 123, 90, 56, 24, 113, 131
Offset: 0

Views

Author

Antti Karttunen, May 11 2021

Keywords

Comments

Coincides with A344026 on Fibbinary numbers, A003714.

Crossrefs

Cf. A000079 (positions of ones), A003714, A005940, A069359, A344026, A344182.

Programs

Formula

a(n) = A069359(A005940(1+n)).

A344180 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j) for all i, j >= 0, where f(n) = 0 if n is a Fibbinary number (A003714), otherwise f(n) = n.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 16 2021

Keywords

Comments

For all i, j:
a(i) = a(j) => A085357(i) = A085357(j),
a(i) = a(j) => A213370(i) = A213370(j),
a(i) = a(j) => A344182(i) = A344182(j).

Crossrefs

Cf. A003714 (positions of 1's), A085357, A213370, A344182.
Cf. also A324400.

Programs

  • PARI
    up_to = 65537;
    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; };
    Aux344180(n) = if(!bitand(n,n+n),0,n);
    v344180 = rgs_transform(vector(1+up_to,n,Aux344180(n-1)));
    A344180(n) = v344180[1+n];
Showing 1-3 of 3 results.