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.

A230452 Starting values for which the "comma sum" sequence (cf. A230288) does not end in 989.

Original entry on oeis.org

0, 1, 2, 3, 4, 47, 49, 52, 54, 59, 64, 65, 67, 69, 70, 72, 74, 75, 76, 77, 80, 81, 82, 86, 87, 88, 89, 91, 92, 93, 94, 396, 398, 401, 403, 405, 406, 409, 410, 411, 414, 416, 417, 421, 422, 426, 428, 431, 433, 435, 436, 439, 440, 441, 444, 446, 447
Offset: 0

Views

Author

M. F. Hasler, Oct 19 2013

Keywords

Comments

According to the general rules, the starting value 0 ends in 1, therefore the value 0 has been included here. However, we list it with index 0 since the original sequence A230288 had been *defined* to start 0,5,11... (and ends in 989), so some might consider that 0 should not be here.
This sequence obviously includes all integers beyond 989.

Crossrefs

Cf. A230288, A230450, A230453.

Programs

  • PARI
    for(n=0,999,vecmax(A230288_vec([n],150))==989||print1(n","))

A230453 Number of terms in the "comma sum" sequence (cf. A230288) starting with n, or 0 if it is infinite.

Original entry on oeis.org

2, 1, 1, 1, 1, 122, 121, 121, 120, 120, 122, 121, 121, 120, 120, 120, 120, 119, 118, 119, 120, 120, 119, 118, 119, 118, 118, 117, 117, 117, 118, 118, 117, 117, 117, 117, 116, 116, 116, 116, 117, 116, 116, 116, 116, 115, 115, 4, 115, 4, 115, 115, 4, 115, 4, 114, 114, 114, 114, 3, 114, 114, 114, 114, 3, 3, 113, 3, 113, 2, 3, 113, 3, 113
Offset: 0

Views

Author

M. F. Hasler, Oct 19 2013

Keywords

Comments

A "comma sum" sequence is such that a(n+1)-a(n) = rightmost digit of a(n) + leftmost digit of a(n+1), taking usually the smallest possible solution.
The value a(0)=2 corresponds to the sequence (0,1), not to sequence A230288 starting by definition with 0,5,....
a(n)>0 for all n<396. See A230450 for the sequence starting with 396.

Crossrefs

Cf. A230288, A230450, A230452.

Programs

  • PARI
    for(n=0,196,print1(#A230288_list([n],150),",")) \\ The second argument (nMax) is useful only for n>= 396. If this value (here 150) is printed, this most probably means that the sequence is infinite, a(n)=0.
  • Python
    # uses A230288gen() in A230288
def a(n): return len(list(A230288gen(start=[n])))
print([a(n) for n in range(100)]) # Michael S. Branicky, Nov 03 2024

A230450 "Comma sum" sequence: a(n+1)-a(n) = rightmost digit of a(n) + leftmost digit of a(n+1), use smallest possible solution; starting with 396.

Original entry on oeis.org

396, 406, 416, 426, 436, 446, 456, 466, 476, 486, 496, 507, 519, 533, 541, 547, 559, 573, 581, 587, 599, 614, 624, 634, 644, 654, 664, 674, 684, 694, 705, 717, 731, 739, 755, 767, 781, 789, 806, 820, 828, 844, 856, 870, 878, 894, 907, 923, 935, 949, 967
Offset: 1

Views

Author

M. F. Hasler, Oct 19 2013

Keywords

Comments

The starting value 396 is the first which seems to lead to an infinite sequence; most smaller starting values "converge" to a sequence ending in 989, which has no successor. See A230288 for further discussion.

Links

Crossrefs

Cf. A230288, A230452, A230453.

Programs

Showing 1-3 of 3 results.

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

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