A100896 a(n) has decimal expansion 3nn3.

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

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