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 1-4 of 4 results.

A324120 Binary weight of SumXOR variant of A297168: a(n) = A000120(A324180(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Feb 19 2019

Keywords

Crossrefs

Programs

Formula

a(n) = A000120(A324180(n)).
a(n) <= A324190(n).
a(p^k) = k-1 for all primes p and exponents k >= 1.

A324181 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = A324180(n) for n > 1 and f(1) = -1.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 4, 5, 6, 2, 4, 2, 7, 8, 9, 2, 6, 2, 4, 10, 11, 2, 4, 12, 13, 8, 4, 2, 6, 2, 14, 15, 16, 17, 9, 2, 18, 19, 14, 2, 7, 2, 4, 8, 20, 2, 4, 21, 7, 22, 4, 2, 7, 23, 24, 25, 26, 2, 14, 2, 27, 8, 28, 29, 11, 2, 4, 30, 7, 2, 4, 2, 31, 10, 4, 32, 13, 2, 24, 33, 34, 2, 24, 35, 36, 37, 38, 2, 7, 39, 4, 40, 41, 42, 4, 2, 11, 8, 43, 2, 16, 2, 44, 10
Offset: 1

Views

Author

Antti Karttunen, Feb 19 2019

Keywords

Comments

For all i, j: a(i) = a(j) => A324120(i) = A324120(j).

Crossrefs

Cf. A000040 (positions of 2's), A156552, A297112, A324120, A324180.
Cf. also A300827, A323914, A324203.

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; };
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n, 0, 2^A297167(n));
    A324180(n) = { my(v=0); fordiv(n, d, if(dA297112(d)))); (v); };
    Aux324181(n) = if((1==n),-n,A324180(n));
    v324181 = rgs_transform(vector(up_to, n, Aux324181(n)));
    A324181(n) = v324181[n];

A324193 a(1) = 0; for n > 1, a(n) = Product_{d|n, d>1, dA297167(d)).

Original entry on oeis.org

0, 1, 1, 2, 1, 6, 1, 6, 3, 10, 1, 54, 1, 14, 15, 30, 1, 90, 1, 150, 21, 22, 1, 1350, 5, 26, 15, 294, 1, 2250, 1, 210, 33, 34, 35, 6750, 1, 38, 39, 5250, 1, 6174, 1, 726, 375, 46, 1, 66150, 7, 350, 51, 1014, 1, 3150, 55, 16170, 57, 58, 1, 1181250, 1, 62, 735, 2310, 65, 23958, 1, 1734, 69, 17150, 1, 1653750, 1, 74, 525, 2166, 77, 39546, 1, 404250, 105
Offset: 1

Views

Author

Antti Karttunen, Feb 20 2019

Keywords

Comments

An auxiliary sequence for defining A300827, which is the restricted growth sequence transform of this sequence. A324202 is a similar sequence, but is not limited to the proper divisors of n, and in contrast to this, also finds the least prime signature representative (A046523) of the product formed.

Crossrefs

Cf. also A324202.

Programs

  • PARI
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A324193(n) = { my(m=1); if(n<=2, n-1, fordiv(n, d, if((d>1)&(dA297167(d)))); (m)); };

Formula

a(1) = 0; for n > 1, a(n) = Product_{d|n, d>1, dA297167(d)).
For all n > 0:
A001222(a(n)) = A000005(n)-2.
A001221(A007913(a(n))) = A324120(n).
A087207(A007913(a(n))) = A324180(n).

A324195 Cumulative bitwise-OR of A297112(d), where d ranges over the divisors d of n.

Original entry on oeis.org

0, 1, 2, 3, 4, 3, 8, 7, 6, 5, 16, 7, 32, 9, 6, 15, 64, 7, 128, 15, 10, 17, 256, 15, 12, 33, 14, 27, 512, 7, 1024, 31, 18, 65, 12, 15, 2048, 129, 34, 31, 4096, 11, 8192, 51, 14, 257, 16384, 31, 24, 13, 66, 99, 32768, 15, 20, 63, 130, 513, 65536, 15, 131072, 1025, 30, 63, 36, 19, 262144, 195, 258, 13, 524288, 31, 1048576, 2049, 14, 387, 24, 35, 2097152, 63, 30
Offset: 1

Views

Author

Antti Karttunen, Feb 20 2019

Keywords

Comments

A324180 differs from this one in that it uses XOR instead of OR, and uses only the proper divisors of n.

Crossrefs

Programs

  • PARI
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n, 0, 2^A297167(n));
    A324195(n) = { my(v=0); fordiv(n, d, v = bitor(v,A297112(d))); (v); };

Formula

A000120(a(n)) = A324190(n).
Showing 1-4 of 4 results.