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 1-5 of 5 results.

A318508 a(n) = A032742(n) AND A001065(n)-A032742(n), where AND is bitwise-and (A004198) and A001065 = sum of proper divisors and A032742 = the largest proper divisor of n.

Original entry on oeis.org

0, 0, 0, 0, 0, 3, 0, 0, 1, 1, 0, 2, 0, 3, 4, 0, 0, 8, 0, 8, 4, 3, 0, 8, 1, 1, 0, 14, 0, 11, 0, 0, 0, 1, 6, 0, 0, 3, 4, 20, 0, 1, 0, 18, 2, 3, 0, 16, 1, 16, 0, 16, 0, 3, 2, 4, 0, 1, 0, 14, 0, 3, 20, 0, 4, 33, 0, 0, 4, 35, 0, 4, 0, 1, 24, 2, 8, 35, 0, 0, 9, 1, 0, 34, 0, 3, 4, 32, 0, 33, 8, 14, 4, 3, 2, 32, 0, 16, 0, 2, 0, 51, 0, 52, 32
Offset: 1

Views

Author

Antti Karttunen, Aug 28 2018

Keywords

Crossrefs

Programs

Formula

a(n) = A004198(A032742(n), A318505(n)).
For n > 1, a(n) = A001065(n) - A318506(n) = (A001065(n) - A318507(n))/2.

A318507 a(n) = A032742(n) XOR A001065(n)-A032742(n), where XOR is bitwise-or (A003987) and A001065 = sum of proper divisors and A032742 = the largest proper divisor of n.

Original entry on oeis.org

1, 1, 1, 3, 1, 0, 1, 7, 2, 6, 1, 12, 1, 4, 1, 15, 1, 5, 1, 6, 3, 8, 1, 20, 4, 14, 13, 0, 1, 20, 1, 31, 15, 18, 1, 55, 1, 16, 9, 10, 1, 52, 1, 4, 29, 20, 1, 44, 6, 11, 21, 14, 1, 60, 13, 56, 23, 30, 1, 80, 1, 28, 1, 63, 11, 12, 1, 58, 19, 4, 1, 115, 1, 38, 1, 60, 3, 20, 1, 106, 22, 42, 1, 72, 23, 40, 25, 28, 1, 78, 5, 48, 27, 44, 21, 92, 1
Offset: 1

Views

Author

Antti Karttunen, Aug 28 2018

Keywords

Comments

Note that here zeros occur only on even perfect numbers (even terms of A000396), in contrast to A318457, which would be zero also for any hypothetical odd perfect number. - Antti Karttunen, Aug 29 2018

Crossrefs

Programs

Formula

a(n) = A003987(A032742(n), A318505(n)).
For n > 1, a(n) = A001065(n) - 2*A318508(n).

A318516 a(n) = A032742(n) OR n-A032742(n), where OR is bitwise-or (A003986) and A032742 = the largest proper divisor of n.

Original entry on oeis.org

1, 1, 3, 2, 5, 3, 7, 4, 7, 5, 11, 6, 13, 7, 15, 8, 17, 9, 19, 10, 15, 11, 23, 12, 21, 13, 27, 14, 29, 15, 31, 16, 31, 17, 31, 18, 37, 19, 31, 20, 41, 21, 43, 22, 31, 23, 47, 24, 47, 25, 51, 26, 53, 27, 47, 28, 55, 29, 59, 30, 61, 31, 63, 32, 61, 33, 67, 34, 63, 35, 71, 36, 73, 37, 59, 38, 75, 39, 79, 40, 63, 41, 83, 42
Offset: 1

Views

Author

Antti Karttunen, Aug 28 2018

Keywords

Crossrefs

Programs

Formula

a(n) = A003986(A032742(n), A060681(n)).
a(n) = n - A318518(n).

A318518 a(n) = A032742(n) AND n-A032742(n), where AND is bitwise-and (A004198) and A032742 = the largest proper divisor of n.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Aug 28 2018

Keywords

Crossrefs

Programs

Formula

a(n) = A004198(A032742(n), A060681(n)).
a(n) = n - A318516(n) = (n - A318517(n))/2.

A318504 SumXOR of divisors of n, up to, but not including the second largest of them A032742(n); a(1) = 0 by convention.

Original entry on oeis.org

0, 0, 0, 1, 0, 3, 0, 3, 1, 3, 0, 4, 0, 3, 2, 7, 0, 6, 0, 2, 2, 3, 0, 10, 1, 3, 2, 0, 0, 9, 0, 15, 2, 3, 4, 7, 0, 3, 2, 0, 0, 15, 0, 12, 14, 3, 0, 22, 1, 12, 2, 10, 0, 29, 4, 6, 2, 3, 0, 26, 0, 3, 12, 31, 4, 27, 0, 22, 2, 5, 0, 5, 0, 3, 8, 20, 6, 17, 0, 4, 11, 3, 0, 14, 4, 3, 2, 18, 0, 3, 6, 16, 2, 3, 4, 46, 0, 10, 0, 5, 0, 53, 0, 24, 26
Offset: 1

Views

Author

Antti Karttunen, Aug 28 2018

Keywords

Crossrefs

Programs

  • PARI
    A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1]));
    A318504(n) = { my(v=0); fordiv(n,d,if(d<A032742(n), v = bitxor(v,d))); (v); };

Formula

a(n) = A032742(n) XOR A227320(n).
For n > 1, a(n) = A106409(n) XOR A178910(n).
Showing 1-5 of 5 results.