A074843 Quadruplets: base 10 representation is the juxtaposition of four identical strings.

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

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