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.

A290082 Restricted growth sequence transform of A289625(A003961(n)).

Original entry on oeis.org

1, 2, 3, 4, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 11, 14, 7, 15, 16, 17, 15, 11, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 23, 30, 31, 32, 33, 34, 20, 35, 36, 37, 30, 38, 39, 40, 41, 42, 19, 43, 44, 45, 37, 46, 47, 23, 48, 49, 50, 19, 51, 52, 43, 53, 54, 34, 55, 56, 57, 58, 59, 60, 61, 62, 30, 63, 64, 65, 66, 42, 67, 68, 34, 69, 30, 70, 71, 68, 72, 61
Offset: 1

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Author

Antti Karttunen, Jul 20 2017

Keywords

Comments

For all i, j: a(i) = a(j) => A003972(i) = A003972(j).

Crossrefs

Programs

  • PARI
    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])); }
    A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ This function from Michel Marcus
    A289625(n) = { my(m=1,p=2,v=znstar(n)[2]); for(i=1,length(v),m *= p^v[i]; p = nextprime(p+1)); (m); };
    write_to_bfile(1,rgs_transform(vector(16384,n,A289625(A003961(n)))),"b290082_upto16384.txt");