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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A297169 Restricted growth sequence transform of a(1) = -1, a(n) = A297168(n) for n > 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Feb 27 2018

Keywords

Comments

For all i, j: A300827(i) = A300827(j) => a(i) = a(j). - Antti Karttunen, Mar 13 2018

Crossrefs

Programs

  • PARI
    allocatemem(2^30);
    up_to = 8192;
    rgs_transform(invec) = { my(occurrences = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(occurrences,invec[i]), my(pp = mapget(occurrences, invec[i])); outvec[i] = outvec[pp] , mapput(occurrences,invec[i],i); outvec[i] = u; u++ )); outvec; };
    write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
    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));
    A297168v1(n) = if(1==n,-1,sumdiv(n,d,(dA297112(d)));
    write_to_bfile(1,rgs_transform(vector(up_to,n,A297168v1(n))),"b297169.txt");
    \\ (More efficient PARI program) - Antti Karttunen, Mar 13 2018

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).

A324538 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = A324537(n) for all other numbers, except f(1) = 0.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 07 2019

Keywords

Comments

For all i, j:
a(i) = a(j) => A069513(i) = A069513(j),
a(i) = a(j) => A324191(i) = A324191(j).

Crossrefs

Cf. A000961 (positions of terms <= 2), A069513, A297167, A324191, A324537.

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));
    A003557(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); }; \\ From A003557
    A324537(n) = { my(m=1); fordiv(n, d, if(d>2, m *= prime(A297167(d)))); A003557(m); };
    Aux324538(n) = if(1==n,0,A324537(n));
    v324538 = rgs_transform(vector(up_to,n,Aux324538(n)));
    A324538(n) = v324538[n];

A329374 a(1) = 0; for n > 1, a(n) = A000265(A329372(n)), where A329372 is Dirichlet convolution of the identity function with A156552.

Original entry on oeis.org

0, 1, 1, 5, 1, 3, 1, 17, 3, 11, 1, 11, 1, 5, 1, 49, 1, 61, 1, 39, 7, 19, 1, 33, 1, 71, 25, 17, 1, 19, 1, 129, 13, 137, 11, 209, 1, 133, 47, 115, 1, 1, 1, 63, 37, 131, 1, 89, 5, 159, 89, 227, 1, 15, 5, 49, 85, 1039, 1, 63, 1, 129, 31, 321, 35, 29, 1, 429, 83, 25, 1, 605, 1, 4115, 111, 409, 15, 101, 1, 307, 45, 8213, 1, 13, 65, 8203, 655, 179, 1, 335, 25
Offset: 1

Views

Author

Antti Karttunen, Nov 12 2019

Keywords

Crossrefs

Programs

Formula

a(1) = 0; and for n > 1, a(n) = A000265(A329372(n)).

A324285 a(n) = A002487(A297168(n)).

Original entry on oeis.org

0, 0, 0, 1, 0, 2, 0, 2, 1, 3, 0, 3, 0, 4, 2, 3, 0, 4, 0, 5, 3, 5, 0, 4, 1, 6, 2, 7, 0, 5, 0, 4, 4, 7, 2, 7, 0, 8, 5, 7, 0, 7, 0, 9, 3, 9, 0, 5, 1, 5, 6, 11, 0, 8, 3, 10, 7, 10, 0, 9, 0, 11, 5, 5, 4, 13, 0, 13, 8, 6, 0, 10, 0, 12, 4, 15, 2, 19, 0, 9, 3, 13, 0, 11, 5, 14, 9, 13, 0, 11, 3, 17, 10, 15, 6, 6, 0, 6, 7, 9, 0, 25, 0, 16, 5
Offset: 1

Views

Author

Antti Karttunen, Feb 22 2019

Keywords

Crossrefs

Programs

Formula

a(n) = A002487(A297168(n)).
Previous Showing 21-25 of 25 results.