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 1-2 of 2 results.

A319694 Product of A078899(x) for all x encountered when map x -> A252463(x) is iterated, starting from x = A252463(n); a(1) = 1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 2, 6, 1, 6, 1, 2, 2, 1, 1, 8, 6, 1, 6, 2, 1, 6, 1, 24, 2, 1, 6, 30, 1, 1, 2, 8, 1, 6, 1, 2, 8, 1, 1, 48, 30, 30, 2, 2, 1, 42, 6, 8, 2, 1, 1, 36, 1, 1, 8, 120, 6, 6, 1, 2, 2, 30, 1, 240, 1, 1, 30, 2, 30, 6, 1, 56, 24, 1, 1, 36, 6, 1, 2, 8, 1, 64, 30, 2, 2, 1, 6, 432, 1, 210, 8, 270, 1, 6, 1, 8, 36
Offset: 1

Views

Author

Antti Karttunen, Nov 21 2018

Keywords

Crossrefs

Cf. also A319689.

Programs

  • PARI
    up_to = 16384;
    ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om,invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om,invec[i],(1+pt))); outvec; };
    A006530(n) = if(n>1, vecmax(factor(n)[, 1]), 1);
    v078899 = ordinal_transform(vector(up_to,n,A006530(n)));
    A078899(n) = v078899[n];
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A252463(n) = if(!(n%2),n/2,A064989(n));
    A319694(n) = { my(m=1); while(1<(n=A252463(n)), m *= A078899(n)); (m); };

A319679 Number of distinct prime signatures that occur when map x -> A268674(x) is iterated, starting from x = n, until an even number is reached; a(1) = 0 by convention.

Original entry on oeis.org

0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2
Offset: 1

Views

Author

Antti Karttunen, Nov 20 2018

Keywords

Comments

Number of distinct values that A046523 obtains when applied to n and all the terms above it in that column where it is located in array A083221.

Crossrefs

Cf. also A319689.

Programs

  • PARI
    up_to = 32769;
    v268674 = readvec("./b268674_terms_only-32769.txt"); \\ Prepared from the b-file of A268674.
    A268674(n) = v268674[n];
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523
    A319679(n) = if(1==n,0,my(m=Map(),s,k=0); while(1,if(!mapisdefined(m,s=A046523(n)), mapput(m,s,s); k++); if(!(n%2), return(k)); n = A268674(n)));
Showing 1-2 of 2 results.