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.

A230422 Positions of ones in A230410.

Original entry on oeis.org

1, 8, 14, 16, 18, 22, 33, 35, 37, 41, 45, 51, 53, 57, 61, 71, 75, 82, 87, 96, 106, 116, 118, 120, 124, 128, 134, 136, 140, 144, 154, 158, 165, 170, 179, 189, 198, 200, 206, 208, 212, 216, 226, 230, 237, 242, 251, 261, 270, 272, 280, 289, 293, 300, 305, 314, 324
Offset: 1

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Author

Antti Karttunen, Nov 10 2013

Keywords

Comments

This sequence gives all n at which positions the successive terms A219666(n-1) & A219666(n) in the infinite trunk of the factorial beanstalk differ only in one digit position in their factorial base representations (A007623).
Please see further comments and examples in A230410.

Examples

			14 is included, because A219666(13) = 40 = '1220' in factorial base representation, while A219666(14) = 46 = '1320' in factorial base, and they differ only by their third least significant digit.
16 is included, because A219666(15) = 48 = '2000' in factorial base representation, while A219666(16) = 52 = '2020' in factorial base, and they differ only by their second least significant digit.
		

Crossrefs

Subset: A231718. Cf. also A230410 and A258010 (first differences).

Programs

  • Mathematica
    nn = 10^4; m = 1; While[m! < Floor[6 nn/5], m++]; m; f[n_] := IntegerDigits[n, MixedRadix[Reverse@ Range[2, m]]]; Position[#, 1] &[Function[w, Count[Subtract @@ Map[PadLeft[#, Max@ Map[Length, w]] &, w], k_ /; k != 0]]@ Map[f@ # &, {#1, #2}] & @@@ Partition[#, 2, 1] &@ TakeWhile[Reverse@ NestWhileList[# - Total@ f@ # &, Floor[6 nn/5], # > 0 &], # <= nn &]] // Flatten (* Michael De Vlieger, Jun 27 2016, Version 10.2 *)

Formula

For all n, A230406(a(n)) is one of the terms of A051683.