A367728 a(n) is the denominator of (R(n) - 1)/(n + 1), where R(n) is the digit reversal of n.

1, 1, 3, 2, 5, 3, 7, 4, 9, 5, 1, 6, 13, 7, 3, 8, 17, 9, 19, 2, 21, 2, 23, 24, 25, 26, 27, 28, 29, 30, 31, 8, 3, 17, 5, 9, 37, 19, 39, 10, 41, 42, 43, 4, 45, 46, 47, 48, 49, 50, 51, 26, 53, 27, 5, 28, 57, 29, 59, 30, 61, 62, 63, 64, 13, 6, 67, 68, 69, 14, 71, 9

Offset: 0

Author

Stefano Spezia, Nov 28 2023

Keywords

• nonn
• base
• easy
• frac
• look

Links

• Stefano Spezia, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A004086, A367593, A367727 (numerator).

Programs

Mathematica

a[n_]:=Denominator[(FromDigits[Reverse[IntegerDigits[n]]]-1)/(n+1)]; Array[a,72,0]

PARI

a(n) = denominator((fromdigits(Vecrev(digits(n)))-1)/(n+1)); \\ Michel Marcus, Nov 28 2023