A294688 Palindromes in Narayana's cows sequence (A000930).

1, 2, 3, 4, 6, 9, 88, 595

Offset: 1

Author

Chai Wah Wu, Nov 06 2017

Keywords

• nonn
• base
• more
• hard

Comments

595 is probably the last term.

Crossrefs

Cf. A000930, A002113, A045504, A055391.

Programs

Maple

a := proc(n) if n < 4 then n else
simplify(hypergeom([-n/3, (1-n)/3, (-1-n)/3], [-n/2, (-1-n)/2], -27/4));
convert(%, base, 10); ListTools:-Reverse(%);
if %% = % then add(%[k]*10^(k-1), k=1..nops(%)) else NULL fi fi end:
seq(a(n), n=1..200); # Peter Luschny, Nov 07 2017