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 1-6 of 6 results.

A374033 Lexicographically earliest infinite sequence such that a(i) = a(j) => A278226(A373985(i)) = A278226(A373985(j)), for all i, j >= 1.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 1, 2, 2, 1, 1, 1, 2, 3, 3, 1, 1, 1, 1, 3, 2, 1, 2, 2, 2, 4, 1, 1, 1, 1, 1, 2, 2, 2, 5, 1, 2, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 3, 1, 1, 2, 6, 7, 3, 2, 1, 8, 1, 2, 1, 2, 6, 1, 1, 1, 2, 1, 1, 4, 1, 2, 1, 1, 6, 1, 1, 1, 7, 2, 1, 9, 2, 2, 3, 2, 1, 2, 6, 1, 3, 2, 2, 5, 1, 1, 10, 5, 1, 1, 1, 2, 1
Offset: 1

Views

Author

Antti Karttunen, Jun 27 2024

Keywords

Comments

Restricted growth sequence transform of A278226(A373985(n)).
For all i, j >= 1:
A305800(i) = A305800(j) => a(i) = a(j) => A373989(i) = A373989(j).

Crossrefs

Programs

  • PARI
    up_to = 100000;
    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; };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A278226(n) = A046523(A276086(n));
    A373985(n) = { my(f=factor(n),m=1,s=0); for(i=1, #f~, my(x=prod(i=1,primepi(f[i, 1]),prime(i))); s += f[i, 2]*x; m *= x^f[i, 2]); gcd(m,s); };
    v374033 = rgs_transform(vector(up_to, n, A278226(A373985(n))));
    A374033(n) = v374033[n];

A373158 Fully additive with a(p) = p# for prime p, where x# is the primorial A034386(x).

Original entry on oeis.org

0, 2, 6, 4, 30, 8, 210, 6, 12, 32, 2310, 10, 30030, 212, 36, 8, 510510, 14, 9699690, 34, 216, 2312, 223092870, 12, 60, 30032, 18, 214, 6469693230, 38, 200560490130, 10, 2316, 510512, 240, 16, 7420738134810, 9699692, 30036, 36, 304250263527210, 218, 13082761331670030, 2314, 42, 223092872, 614889782588491410, 14
Offset: 1

Views

Author

Antti Karttunen, May 27 2024

Keywords

Comments

Completely additive with a(p^e) = e * A002110(A000720(p)).

Crossrefs

Programs

  • PARI
    A373158(n) = { my(f=factor(n)); sum(i=1, #f~, f[i, 2]*prod(i=1,primepi(f[i, 1]),prime(i))); }; \\ corrected Jun 25 2024

Formula

From Antti Karttunen, Jun 25 2024, Oct 28 2024: (Start)
a(n) = A276085(A003961(n)).
For n >= 1, a(A000040(n)) = A002110(n), a(A002110(n)) = A060389(n).
(End)

Extensions

Data [first incorrect term was at a(8)] and the faulty PARI-program corrected by Antti Karttunen, Jun 25 2024

A373986 Numerator of A373158(n) / A108951(n), where A108951 is fully multiplicative and A373158 is fully additive with a(p) = p# for prime p, where x# is the primorial A034386(x).

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 3, 1, 8, 1, 5, 1, 53, 1, 1, 1, 7, 1, 17, 6, 578, 1, 1, 1, 7508, 1, 107, 1, 19, 1, 5, 193, 127628, 4, 1, 1, 2424923, 2503, 3, 1, 109, 1, 1157, 7, 55773218, 1, 7, 1, 31, 14181, 15017, 1, 5, 13, 9, 269436, 1617423308, 1, 1, 1, 50140122533, 37, 3, 167, 1159, 1, 255257, 18591073, 121, 1, 1, 1, 1855184533703
Offset: 1

Views

Author

Antti Karttunen, Jun 25 2024

Keywords

Crossrefs

Cf. A108951, A373158, A373985, A373987 (denominators), A373988 (rgs-transform).

Programs

  • PARI
    A373986(n) = { my(f=factor(n),m=1,s=0); for(i=1, #f~, my(x=prod(i=1,primepi(f[i, 1]),prime(i))); s += f[i, 2]*x; m *= x^f[i, 2]); s/gcd(m,s); };
    
  • PARI
    A373986(n) = numerator(A373158(n)/A108951(n));

Formula

a(n) = A373158(n) / A373985(n) = A373158(n) / gcd(A108951(n), A373158(n)).

A373987 Denominator of A373158(n) / A108951(n), where A108951 is fully multiplicative and A373158 is fully additive with a(p) = p# for prime p, where x# is the primorial A034386(x).

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 4, 3, 15, 1, 12, 1, 105, 5, 2, 1, 36, 1, 60, 35, 1155, 1, 4, 15, 15015, 12, 420, 1, 180, 1, 16, 1155, 255255, 105, 9, 1, 4849845, 15015, 20, 1, 1260, 1, 4620, 180, 111546435, 1, 48, 105, 900, 85085, 60060, 1, 108, 385, 70, 1616615, 3234846615, 1, 18, 1, 100280245065, 1260, 16, 5005, 13860, 1, 1021020
Offset: 1

Views

Author

Antti Karttunen, Jun 25 2024

Keywords

Crossrefs

Cf. A108951, A373158, A373985, A373986 (numerators).

Programs

  • PARI
    A373987(n) = { my(f=factor(n),m=1,s=0); for(i=1, #f~, my(x=prod(i=1,primepi(f[i, 1]),prime(i))); s += f[i, 2]*x; m *= x^f[i, 2]); m/gcd(m,s); };
    
  • PARI
    A373987(n) = denominator(A373158(n)/A108951(n));

Formula

a(n) = A108951(n) / A373985(n) = A108951(n) / gcd(A108951(n), A373158(n)).

A373984 a(n) = A108951(n) - A373158(n), where A108951 is fully multiplicative and A373158 is fully additive with a(p) = p# for prime p, where x# is the primorial A034386(x).

Original entry on oeis.org

1, 0, 0, 0, 0, 4, 0, 2, 24, 28, 0, 14, 0, 208, 144, 8, 0, 58, 0, 86, 1044, 2308, 0, 36, 840, 30028, 198, 626, 0, 322, 0, 22, 11544, 510508, 6060, 128, 0, 9699688, 150144, 204, 0, 2302, 0, 6926, 1038, 223092868, 0, 82, 43680, 1738, 2552544, 90086, 0, 412, 66960, 1464, 48498444, 6469693228, 0, 680, 0, 200560490128
Offset: 1

Views

Author

Antti Karttunen, Jun 25 2024

Keywords

Crossrefs

Programs

  • PARI
    A373984(n) = { my(f=factor(n),m=1,s=0); for(i=1, #f~, my(x=prod(i=1,primepi(f[i, 1]),prime(i))); s += f[i, 2]*x; m *= x^f[i, 2]); (m-s); };

A373989 a(n) = A276150(gcd(A108951(n), A373158(n))), where A276150 is the digit sum in primorial base, A108951 is fully multiplicative and A373158 is fully additive with a(p) = p# for prime p, where x# is the primorial A034386(x).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jun 26 2024

Keywords

Crossrefs

Programs

  • PARI
    A276150(n) = { my(s=0, p=2, d); while(n, d = (n%p); s += d; n = (n-d)/p; p = nextprime(1+p)); (s); };
    A373985(n) = { my(f=factor(n),m=1,s=0); for(i=1, #f~, my(x=prod(i=1,primepi(f[i, 1]),prime(i))); s += f[i, 2]*x; m *= x^f[i, 2]); gcd(m,s); };
    A373989(n) = A276150(A373985(n));

Formula

a(n) = A276150(A373985(n)).
Showing 1-6 of 6 results.