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.

A166064 Sum of first n terms divides the concatenation of the first n terms.

Original entry on oeis.org

1, 0, 2, 6, 8, 10, 162, 420, 174, 486, 974, 4486, 1794, 20834, 26986, 16098, 19220, 19738, 58362, 60918, 48564, 87476, 38602, 579030, 231612, 587034, 1375080, 6356154, 951846, 1038240, 205702, 2409400, 4039834
Offset: 1

Views

Author

Zak Seidov, Oct 05 2009

Keywords

Comments

Based on Eric Angelini's post to seqfan list Sep 29 2009 (see A151995).
Version with a(1)=1, a(n) is smallest nonnegative integer not yet used.

Examples

			(1+0=1)|10, (1+0+2=3)|102, (1+0+2+6=9)|1026, etc.

Crossrefs

Cf. A151995, A152210.

A165770 Smallest divisor of 123...n (=A007908) larger than the preceding term.

Original entry on oeis.org

1, 2, 3, 617, 823, 1286, 9721, 14593, 32463, 1234567891, 1417414341, 2110805449, 98220894641, 205761315168520219, 8230452606740808761, 3086419727527803285379, 8755800645468945490437, 70708355728013820970883
Offset: 1

Views

Author

M. F. Hasler, Sep 30 2009

Keywords

Comments

Inspired by Layman's comment on a sequence from Angelini, cf. link.

Links

Crossrefs

Cf. A151995.

Programs

  • PARI
    c=""; s=0; for(i=1,19, fordiv(c=eval(Str(c,i)),d, d>s || next; print1(s=d,", "); break))

Extensions

Edited by Charles R Greathouse IV, Apr 24 2010

A152210 a(1)=1; thereafter a(n) is smallest number > a(n-1) such that the sum a(1)+...+a(n) divides the concatenation a(1)...a(n).

Original entry on oeis.org

1, 2, 6, 250488, 279786, 1060566, 1414088, 1767610, 2447460, 10031652, 10356624, 50373066, 155962698, 193715622, 375287934, 759659778, 3125214762, 3252158280, 21173281128, 22937721222, 104101965546, 164092928742, 284358161736
Offset: 1

Views

Author

N. J. A. Sloane, Oct 07 2009, based on a posting to the Sequence Fans Mailing List by Eric Angelini, Sep 29 2009

Keywords

Comments

See A151995 for the nonmonotonic version.

Examples

			1+2 (=3) divides 12 --> HIT
1+2+3 (=6) does not divide 123
1+2+4 (=7) does not divide 124
1+2+5 (=8) does not divide 125
1+2+6 (=9) divides 126 --> HIT
...

Crossrefs

Cf. A151995, A166064, A165770, A165771.

Extensions

Corrected by Zak Seidov, Oct 08 2009
a(14)-a(20) from Donovan Johnson, Jul 20 2010
a(21)-a(23) from Max Alekseyev, Jun 18 2011

A165771 Smallest positive integer such that a(1)+...a(n) divides 123...n (=A007908(n)).

Original entry on oeis.org

1, 1, 1, 614, 206, 463, 8435, 4872, 17870, 1234535428, 182846450, 693391108, 96110089192, 205761216947625578, 8024691291572288542, 3078189274921062476618, 5669380917941142205058, 61952555082544875480446
Offset: 1

Views

Author

M. F. Hasler, Sep 30 2009

Keywords

Comments

Without the initial term, these are the first differences of A165770.

Links

Crossrefs

Cf. A151995, A165770, A166064.

Programs

  • PARI
    c=""; s=0; for(i=1,19, fordiv(c=eval(Str(c,i)),d, d>s || next; print1(d-s,", "); s=d; break))

Extensions

Edited by Charles R Greathouse IV, Apr 24 2010
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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