A069511 Numbers in which starting from most significant digit the n-th digit is obtained by adding n to the (n-1)-st digit (the digit to the left of it) and then ignoring the carry. Alternately the n-th digit starting from the most significant digit is the n-th triangular number mod 10.

1, 13, 136, 1360, 13605, 136051, 1360518, 13605186, 136051865, 1360518655, 13605186556, 136051865568, 1360518655681, 13605186556815, 136051865568150, 1360518655681506, 13605186556815063, 136051865568150631, 1360518655681506310, 13605186556815063100

Offset

1,2

Links

Table of n, a(n) for n=1..20.

Formula

a(n) = 10 * a(n-1) + (A000217(n) mod 10) with a(0)=0. - Sean A. Irvine, May 02 2024

Crossrefs

Cf. A000217.

Sequence in context: A019519 A243216 A112225 * A052262 A065550 A078795

Adjacent sequences: A069508 A069509 A069510 * A069512 A069513 A069514

Keyword

nonn,base

Author

Amarnath Murthy, Mar 30 2002

Extensions

Offset corrected and more terms from Sean A. Irvine, May 02 2024

Status

approved