A087553 - OEIS

A087553

Squares in which the neighboring digits differ at most by 1. Neighbors of 1 are 0 and 2, neighbors of 0 are 1 and 9.

0, 1, 4, 9, 100, 121, 676, 900, 10000, 12100, 12321, 90000, 1000000, 1210000, 1232100, 1234321, 9000000, 100000000, 121000000, 123210000, 123432100, 123454321, 900000000, 10000000000, 11122233444, 12100000000, 12321000000, 12343210000

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OFFSET

1,3

COMMENTS

The sequence is infinite with trivial terms like 10^(2k) and 9*10^(2k). Conjecture: There are infinitely many nontrivial terms.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..63

EXAMPLE

12321, 1345678987654321 are terms.

CROSSREFS

Intersection of A000290 and A376425.

Sequence in context: A069707 A129967 A182020 * A061850 A061459 A061869

Adjacent sequences: A087550 A087551 A087552 * A087554 A087555 A087556

KEYWORD

base,nonn,changed

AUTHOR

Amarnath Murthy, Sep 13 2003

EXTENSIONS

More terms from Sascha Kurz, Sep 22 2003

Offset changed and 0 inserted by Andrew Howroyd, Sep 22 2024

STATUS

approved