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A100896 a(n) has decimal expansion 3nn3. 5
3003, 3113, 3223, 3333, 3443, 3553, 3663, 3773, 3883, 3993, 310103, 311113, 312123, 313133, 314143, 315153, 316163, 317173, 318183, 319193, 320203, 321213, 322223, 323233, 324243, 325253, 326263, 327273, 328283, 329293, 330303, 331313, 332323 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = 3nn3 where n=0, 1, 2, 3, ...

a(n) = 3*(1+10^(2*d+1))+n*(10+10^(d+1)) where d = A055642(n). - Robert Israel, Mar 08 2018

EXAMPLE

If n=5, then 3nn3 is 3553.

MAPLE

f:= proc(n) local d; d:= ilog10(n)+1; 3*(1+10^(2*d+1))+n*(10+10^(d+1)) end proc:

3003, seq(f(n), n=1..100); # Robert Israel, Mar 08 2018

MATHEMATICA

FromDigits/@Table[Join[{3}, IntegerDigits[i], IntegerDigits[i], {3}], {i, 0, 40}] (* Harvey P. Dale, Sep 22 2014 *)

PROG

(MAGMA) [3003] cat [3*(1+10^(2*#Intseq(n)+1))+n*(10+10^(#Intseq(n)+1)): n in [1..40]]; // Vincenzo Librandi, Mar 09 2018

CROSSREFS

Cf. A100846.

Sequence in context: A128935 A145304 A094336 * A324405 A140915 A140928

Adjacent sequences:  A100893 A100894 A100895 * A100897 A100898 A100899

KEYWORD

nonn,base,easy

AUTHOR

Parthasarathy Nambi, Jan 10 2005

EXTENSIONS

More terms from Brian Lauer (bel136(AT)psu.edu), Feb 21 2006

Offset changed to 0 by Robert Israel, Mar 08 2018

STATUS

approved

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Last modified May 30 18:07 EDT 2020. Contains 334728 sequences. (Running on oeis4.)