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

Author

N. J. A. Sloane, May 06 2006

Keywords

• nonn
• base
• look

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.

Crossrefs

Cf. A117828, A117816, A117817.

Programs

Haskell

a118532 n = a118532_list !! (n-1)
a118532_list = iterate ((+ 15) . a004086) 1
-- Reinhard Zumkeller, Jan 29 2014

PARI

A118532(Nmax,Q=15,S=1)=vector(Nmax,i,if(i>1,S=A004086(S)+Q,S)) \\ - M. F. Hasler, May 06 2012

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