A093021 Indices of terms in A093019 with value 1.

9, 14, 28, 33, 47, 52, 66, 71, 85, 90, 108, 113, 127, 132, 146, 151, 165, 170, 189, 194, 207, 212, 226, 231, 245, 250, 269, 274, 288, 293, 306, 311, 325, 330, 349, 354, 368, 373, 387, 392, 405, 410, 429, 434, 448, 453, 467, 472, 486, 491, 504, 518, 523, 537

Offset: 1

Author

Ray Chandler, Apr 03 2004

Keywords

• easy
• nonn
• base

Comments

Integers which require a following 1 to have a valid Luhn mod 10 check digit.

Examples

			14 is in the sequence because A093019(14)=1; 141 has a valid Luhn mod 10 check digit.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• John Kilgo, Using the Luhn Algorithm, DotNetJohn.com.
• Webopedia, Luhn formula
• Wikipedia, Luhn algorithm
• Index entries for sequences related to decimal expansion of n

Crossrefs

Cf. A093017-A093029.

Programs

Haskell

a093021 n = a093021_list !! (n-1)
a093021_list = filter ((== 1) . a093019) [0..]
-- Reinhard Zumkeller, Nov 08 2014

Formula

A093019(a(n)) = 1. - Reinhard Zumkeller, Nov 08 2014

Extensions

Offset changed by Reinhard Zumkeller, Nov 08 2014