Error-finding program

[Don Reble]

Seqfans:

David Wilson asks,
> Some very common errors in OEIS sequences are:
> - Lexically splitting elements
> - Lexically joining adjacent elements
> - Omitting elements
> - Transposing elements
> Might it be possible to [automatically] detect and flag ... suspicious
> elements?

    Well, one could seek almost-monotonic sequences.

Russ Cox asks,
> What makes you believe these errors are very common?

    Having sought almost-monotonic sequences, I observe that
    some sequences...

    ... are obviously monotonic and wrong:
A003145 A005906 A014254 A014431 A015883 A015958 A024609 A024968 A024976
A033289 A033563 A038656 A045725 A046231 A046868 A046956 A047119 A048425
A049149 A051395 A051662 A051673 A055730 A057214 A058048 A061437 A061793
A065296 A066176 A066697 A066794 A067589 A069791 A070255 A070993 A072422
A073301 A074150 A075010 A076132 A076770 A076798 A077535 A078790 A079047
A080902 A081322 A082518 A082767 A083043 A083374 A083897 A084197 A084198
A085269 A085739 A086170 A088579 A090658 A090679 A092112 A098795 A100145
A100456 A104670 A105280 A106535 A107680 A107687 A108539 A108543 A108547
A108220 A110803 A110952 A112735 A113034 A113317 A113405 A114850 A115049
A117092 A117124 A117581 A117601 A118061 A118378 A120453 A120876 A120890
A121028 A121037 A121039 A121442

    ... are probably monotonic-and-wrong:
A004993 A005620 A022041 A026001 A037140 A037458 A052396 A052468 A056267
A056514 A057886 A060774 A061672 A063040 A067057 A072561 A072810 A085611
A113174

    ... are wrong (whether monotonic or not):
A077525 A082257 A104189 A104362

    ... are suspicious:
A005467 A007769 A026013 A026127 A026299 A026302 A026307 A030278 A051526
A051550 A054499 A055918 A064571 A074030 A074352 A082674 A082675 A087525
A088460 A097926 A100545 A101234 A114497 A114498 A117504 A117988 A118058
A119626 A121210 A121331 A122718

    ... have surprising trailing zeroes:
A026468 A026469 A026470 A030755 A030795 A037533 A037534 A048060 A048070
A049681 A054114

    ... have STU/VWX mismatches:
A120002 A121049

    So, yeah, the errors are common.


    Anyway, thanks a bunch for that idea, David. :-)

-- 
Don Reble  djr at nk.ca


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