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.

A356164 a(n) is the smallest positive k such that n divides k*A003961(k), where A003961 is fully multiplicative with a(p) = nextprime(p).

Original entry on oeis.org

1, 2, 2, 4, 3, 2, 5, 8, 4, 6, 7, 4, 11, 10, 3, 16, 13, 4, 17, 12, 10, 14, 19, 8, 9, 22, 8, 20, 23, 6, 29, 32, 14, 26, 5, 4, 31, 34, 22, 24, 37, 10, 41, 28, 6, 38, 43, 16, 25, 18, 26, 44, 47, 8, 21, 40, 34, 46, 53, 12, 59, 58, 20, 64, 33, 14, 61, 52, 38, 10, 67, 8, 71, 62, 9, 68, 7, 22, 73, 48, 16, 74, 79, 20, 39, 82
Offset: 1

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Author

Antti Karttunen, Jul 28 2022

Keywords

Comments

a(n) is the smallest positive k such that A191002(k) is a multiple of n.

Crossrefs

Programs

  • PARI
    A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
    A356164(n) = for(k=1, oo, if((k*A003961(k))%n==0, return(k)));

Formula

a(n) = n - A356165(n).
For n >= 2, a(A000040(n)) = A000040(n-1).

A356166 Greatest common divisor of n and the smallest positive k such that n divides k*A003961(k), where A003961 is fully multiplicative with a(p) = nextprime(p).

Original entry on oeis.org

1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 4, 1, 2, 3, 16, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 4, 1, 6, 1, 32, 1, 2, 5, 4, 1, 2, 1, 8, 1, 2, 1, 4, 3, 2, 1, 16, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 1, 12, 1, 2, 1, 64, 1, 2, 1, 4, 1, 10, 1, 8, 1, 2, 3, 4, 7, 2, 1, 16, 1, 2, 1, 4, 1, 2, 1, 8, 1, 6, 1, 4, 1, 2, 1, 32, 1, 2, 1, 4, 1, 2, 1, 8, 5
Offset: 1

Views

Author

Antti Karttunen, Jul 28 2022

Keywords

Crossrefs

Cf. A003961, A191002, A356164, A356165, A356167, A356168, A356171 (positions of 1's), A356172.
Cf. also A345992, A356151.

Programs

  • PARI
    A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
    A356166(n) = for(k=1, oo, if((k*A003961(k))%n==0, return(gcd(n,k))));

Formula

a(n) = gcd(n, A356164(n)) = gcd(n, A356165(n)) = gcd(A356164(n), A356165(n)).

A356168 Greatest common divisor of n and A003961(A356164(n)), where A356164(n) is the smallest positive k such that n divides k*A003961(k), and A003961 is fully multiplicative with a(p) = nextprime(p).

Original entry on oeis.org

1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 11, 3, 13, 7, 5, 1, 17, 9, 19, 5, 21, 11, 23, 3, 25, 13, 27, 7, 29, 15, 31, 1, 33, 17, 7, 9, 37, 19, 39, 5, 41, 21, 43, 11, 15, 23, 47, 3, 49, 25, 51, 13, 53, 27, 55, 7, 57, 29, 59, 15, 61, 31, 63, 1, 65, 33, 67, 17, 69, 7, 71, 9, 73, 37, 25, 19, 11, 39, 79, 5, 81, 41, 83, 21, 85, 43
Offset: 1

Views

Author

Antti Karttunen, Jul 28 2022

Keywords

Crossrefs

Programs

  • PARI
    A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
    A356168(n) = for(k=1, oo, if((k*A003961(k))%n==0, return(gcd(n,A003961(k)))));

Formula

a(n) = gcd(n, A003961(A356164(n))).
a(n) = gcd(n, A356169(n)) = n - A356169(n).
Showing 1-3 of 3 results.