A118532 Start with 1 and repeatedly reverse the digits and add 15 to get the next term.

1, 16, 76, 82, 43, 49, 109, 916, 634, 451, 169, 976, 694, 511, 130, 46, 79, 112, 226, 637, 751, 172, 286, 697, 811, 133, 346, 658, 871, 193, 406, 619, 931, 154, 466, 679, 991, 214, 427, 739, 952, 274, 487, 799, 1012, 2116, 6127, 7231, 1342, 2446

Offset

1,2

Comments

This sequence never cycles.

The plot (see the Noe link) shows 2774 terms of this sequence. It has a regular structure, which continues at higher decades. - T. D. Noe, May 10 2006

Links

T. D. Noe, Table of n, a(n) for n = 1..2774

T. D. Noe, Plot of A118532

N. J. A. Sloane and others, Sequences of RADD type, OEIS wiki.

Formula

This sequence never cycles. After a while, the pattern of length changes settles into an increasing pattern: 10^(4m)+3, 10^(4m+1)+3, 10^(4m+2)+12, 10^(4m+3)+12, 10^(4(m+1))+3, ... The key is that every two steps adds 15 at each end, unless there is a carry across the middle or a trailing 0. This allows many steps to be carried out in a single operation. - Martin Fuller, May 12 2006

a(n+1) = A004086(a(n)) + 15. - Reinhard Zumkeller, Jan 29 2014

Prog

(PARI) A118532(Nmax, Q=15, S=1)=vector(Nmax, i, if(i>1, S=A004086(S)+Q, S)) \\ - M. F. Hasler, May 06 2012
(Haskell)
a118532 n = a118532_list !! (n-1)
a118532_list = iterate ((+ 15) . a004086) 1
-- Reinhard Zumkeller, Jan 29 2014

Crossrefs

Cf. A117828, A117816, A117817.

Sequence in context: A189949 A103111 A118862 * A253691 A300919 A007834

Adjacent sequences: A118529 A118530 A118531 * A118533 A118534 A118535

Keyword

nonn,base,look

Author

N. J. A. Sloane, May 06 2006

Status

approved