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 A074843 Quadruplets: base 10 representation is the juxtaposition of four identical strings. 1
 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, 10101010, 11111111, 12121212, 13131313, 14141414, 15151515, 16161616, 17171717, 18181818, 19191919, 20202020, 21212121, 22222222, 23232323, 24242424, 25252525 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Doublets in which the index is also a doublet. - Jamie Robert Creasey, Jun 23 2021 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 FORMULA A020338(A020338(n)). - Jamie Robert Creasey, Jun 23 2021 MATHEMATICA Table[FromDigits[Flatten[IntegerDigits/@PadRight[{}, 4, n]]], {n, 30}] (* Harvey P. Dale, Dec 20 2021 *) PROG (UBASIC) 10 cls 30 for I=1 to 100 40 A=str(I) 50 C=A+A+A+A 60 B=val(cutspc(C)) 80 print B 90 next 100 end (PARI) a(n)=eval(Str(n, n, n, n)) \\ Charles R Greathouse IV, Jun 23 2021 CROSSREFS Cf. A020338. Sequence in context: A033285 A085109 A346000 * A175464 A326110 A043496 Adjacent sequences: A074840 A074841 A074842 * A074844 A074845 A074846 KEYWORD easy,nonn,base AUTHOR Felice Russo, Sep 10 2002 STATUS approved

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Last modified October 1 11:02 EDT 2023. Contains 365819 sequences. (Running on oeis4.)