A160943 a(n) = n + digital sum(n-1) + digital sum(n+1).

3, 6, 9, 12, 15, 18, 21, 24, 18, 21, 15, 18, 21, 24, 27, 30, 33, 36, 30, 33, 27, 30, 33, 36, 39, 42, 45, 48, 42, 45, 39, 42, 45, 48, 51, 54, 57, 60, 54, 57, 51, 54, 57, 60, 63, 66, 69, 72, 66, 69, 63, 66, 69, 72, 75, 78, 81, 84, 78, 81, 75, 78, 81, 84, 87, 90, 93, 96, 90, 93

Offset: 1

Author

Claudio Meller, May 30 2009

Keywords

• nonn
• base

Examples

			a(8)  = 8 +ds(7) +ds(9)  = 7+8+9  = 24;
a(15) = 15+ds(14)+ds(16) = 15+5+7 = 27;
a(26) = 26+ds(25)+ds(27) = 26+7+9 = 42.
		

Crossrefs

Cf. A007953, A062028, A160939.

Programs

Mathematica

Table[n+Total[IntegerDigits[n-1]]+Total[IntegerDigits[n+1]],{n,70}] (* Harvey P. Dale, Jun 24 2011 *)

PARI

a(n) = n + sumdigits(n-1) + sumdigits(n+1); \\ Michel Marcus, Mar 11 2021

Python

def A160943(n): return n+sum(int(d) for d in str(n-1))+sum(int(d) for d in str(n+1)) # Chai Wah Wu, Mar 11 2021

Formula

a(n) = n + A007953(n-1) + A007953(n+1)