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.

A333723 Successive products a(n) * a(n+1) of A333722. Each product contains a substring present both in A333722(n) and A333722(n+1).

Original entry on oeis.org

10, 110, 132, 24, 42, 315, 75, 125, 725, 812, 672, 528, 572, 156, 96, 576, 1332, 1443, 1326, 476, 182, 39, 93, 713, 621, 1917, 497, 679, 6693, 3864, 2520, 1575, 1330, 684, 864, 384, 648, 1377, 799, 1974, 1848, 1804, 164, 184, 1840, 800, 600, 1500, 2550, 2652, 2756, 2915, 3135, 3705, 3510, 2646, 931, 1159, 3660
Offset: 1

Views

Author

Eric Angelini and Jean-Marc Falcoz, Apr 03 2020

Keywords

Examples

			a(10) = 812 and 812 is the product of two terms containing the substring 2, which are A333722(10) = 29 and A333722(11) = 28.
		

Crossrefs

Cf. A333722.

A333724 Largest digit that is shared in A333722 by the pair a(n), a(n+1) and the product a(n) * a(n+1).

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 5, 5, 2, 2, 2, 2, 2, 6, 6, 6, 3, 3, 3, 4, 1, 3, 3, 3, 2, 7, 7, 7, 9, 6, 5, 5, 3, 8, 8, 8, 8, 1, 7, 4, 4, 4, 4, 4, 4, 0, 0, 0, 5, 5, 5, 5, 5, 5, 5, 4, 9, 1, 6, 6, 6, 6, 6, 6, 6, 6, 6, 8, 5, 5, 5, 8, 3, 3, 3, 3, 2, 2, 9, 8, 0, 0, 9, 9, 9, 9, 9, 5, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 6, 8, 7, 7, 7, 7, 7, 8
Offset: 1

Views

Author

Eric Angelini and Jean-Marc Falcoz, Apr 03 2020

Keywords

Examples

			a(10) = 2, as 2 is the largest digit shared by A333722(10) = 29, A333722(11) = 28 and by the product 29 * 28 = 812 = A333724(10).
		

Crossrefs

Cf. A333722, A333723 (the products).

A333933 Lexicographically earliest sequence of distinct positive integers such that a(n), a(n+1) and the product a(n)*a(n+1) have in common the substring n.

Original entry on oeis.org

1, 12, 23, 134, 145, 65, 567, 278, 289, 910, 110, 10112, 1213, 1413, 15014, 16154, 16817, 17018, 18719, 19201, 2120, 2218, 10223, 2324, 24251, 2526, 27026, 52827, 28291, 29303, 30310, 3231, 32733, 6334, 34351, 35036, 36373, 37388, 39385, 139240, 4041, 41428, 34342, 15443, 4445, 45461, 46847, 34847, 48149
Offset: 1

Views

Author

Jean-Marc Falcoz and Eric Angelini, Apr 10 2020

Keywords

Examples

			a(1) = 1, a(2) = 12 and the product a(1)*a(2) = 12 have n = 1 in common;
a(2) = 12, a(3) = 23 and the product a(2)*a(3) = 276 have n = 2 in common;
a(3) = 23, a(4) = 134 and the product a(3)*a(4) = 3082 have n = 3 in common;
a(4) = 134, a(5) = 145 and the product a(4)*a(5) = 19430 have n = 4 in common;
...
a(120) = 11912061, a(121) = 1012120 and their product 12056435179320 share the substring 120; etc.
		

Crossrefs

A333722 (presents the same idea, but without the constraint of the substring being n).

Programs

  • Mathematica
    a[1]=1;a[n_]:=a[n]=Block[{k=1},While[MemberQ[Array[a,n-1],k]||!(Q=StringContainsQ)[(T=ToString)@k,T@n]||!And@@(Q[T@#,T[n-1]]&/@{a[n-1],k,a[n-1]*k}),k++];k];Array[a,26] (* Giorgos Kalogeropoulos, May 12 2022 *)
Showing 1-3 of 3 results.