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 1-4 of 4 results.

A065926 Index values for new maxima in A065925.

Original entry on oeis.org

1, 3, 5, 21, 25, 35, 55, 185, 265, 563, 569, 733, 3350, 3469, 6010, 6779, 10689, 11143, 14505, 18016, 30561, 31588, 37757, 59611, 65816, 67106, 75904, 118361, 214379, 241564, 255196, 414221, 648152, 703812, 881848, 1153107, 1277048, 1407769, 1719552, 1775846, 2722607, 3177728
Offset: 1

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Author

Jason Earls, Nov 28 2001

Keywords

References

  • J. Earls, Mathematical Bliss, Pleroma Publications, 2009, pages 99-100. ASIN: B002ACVZ6O [From Jason Earls, Nov 26 2009]

Crossrefs

Programs

  • PARI
    sopf(n) = local(fac, i); fac=factor(n); sum(i=1,matsize(fac)[1],fac[i,1])
    A065926(m)= {local(a,n,k); a=0; for(k=1,m,n=1; while(sopf(n)!=sopf(n+k), n++); if(n>a,a=n; print1(k,",")))} \\ Klaus Brockhaus

Extensions

More terms from David Wasserman, Sep 19 2002
More terms from Sean A. Irvine, Sep 20 2023

A065927 Records in A065925.

Original entry on oeis.org

5, 7, 114, 209, 493, 516, 855, 1194, 1274, 2815, 2834, 3180, 3186, 5225, 6010, 8056, 8357, 8954, 11439, 13684, 14599, 15748, 17298, 17384, 17784, 20940, 25886, 36223, 36938, 41796, 53725, 64855, 67942, 69167, 72468, 79143, 79516, 86232, 96845, 120708, 125709
Offset: 1

Views

Author

Jason Earls, Nov 28 2001

Keywords

Crossrefs

Programs

  • PARI
    sopf(n) = local(fac, i); fac=factor(n); sum(i=1,matsize(fac)[1],fac[i,1])
    A065927(m)= {local(a,n,k); a=0; for(k=1,m,n=1; while(sopf(n)!=sopf(n+k), n++); if(n>a,a=n; print1(n,",")))} // Klaus Brockhaus

Extensions

More terms from David Wasserman, Sep 19 2002
More terms from Sean A. Irvine, Sep 21 2023

A065569 Smallest k such that omega(n+k) = omega(k).

Original entry on oeis.org

2, 2, 2, 3, 2, 2, 2, 3, 2, 3, 2, 4, 3, 2, 2, 3, 2, 5, 4, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 2, 14, 5, 4, 3, 2, 5, 4, 3, 2, 3, 2, 5, 4, 3, 2, 3, 2, 5, 4, 3, 2, 6, 8, 5, 4, 3, 2, 3, 2, 4, 3, 2, 4, 3, 2, 5, 4, 3, 2, 3, 2, 7, 8, 5, 4, 3, 2, 3, 2, 3, 2, 6, 10, 5, 4, 3, 2, 6, 6, 6, 15, 5, 4, 3, 2, 5, 4, 3, 2, 3, 2, 5, 4
Offset: 1

Views

Author

Jason Earls, Nov 30 2001

Keywords

Crossrefs

Programs

  • PARI
    a(n)= {for(k=1, oo, if(omega(k)==omega(n+k), return(k)))}

A280943 Least number k such that sopfr(k) = sopfr(k + n), where sopfr(k) is the integer log of k.

Original entry on oeis.org

5, 10, 7, 20, 7, 14, 20, 40, 13, 14, 21, 28, 14, 40, 19, 33, 11, 26, 56, 28, 49, 42, 115, 56, 35, 28, 31, 57, 11, 38, 50, 66, 63, 11, 17, 52, 11, 112, 42, 51, 22, 98, 11, 84, 57, 35, 52, 95, 138, 13, 33, 56, 22, 62, 77, 114, 61, 22, 39, 76, 44, 13, 91, 57, 70
Offset: 1

Views

Author

Paolo P. Lava, Jan 11 2017

Keywords

Examples

			a(1) = 5 because 5 is the least number such that sopfr(5) = sopfr(5 + 1) = 5 .
a(2) = 10 because 10 is the least number such that sopfr(10) = sopfr(10 + 2) = 7 .
		

Crossrefs

Programs

  • Maple
    with(numtheory):P:=proc(q) local a,b,k,n; for n from 1 to q do for k from 1 to q do
    a:=ifactors(k)[2]; b:=ifactors(k+n)[2];
    if add(a[k][1]*a[k][2],k=1..nops(a))=add(b[k][1]*b[k][2],k=1..nops(b))
    then print(k); break; fi; od; od; end: P(10^9);
Showing 1-4 of 4 results.