A308561 Numbers with no 0 digit that are divisible by the sum of any two of their digits at distinct positions.

1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 18, 21, 24, 27, 36, 42, 45, 48, 54, 63, 72, 81, 84, 252, 1212, 1512, 2112, 2424, 2772, 3636, 4224, 4848, 6216, 6336, 8316, 8448, 11112, 11116, 21252, 22212, 22224, 22512, 33336, 34944, 43344, 44424, 44448, 66636, 77112, 86688, 88848, 99792, 111216, 111636

Offset

1,2

Comments

Without the constraint of having no digit 0, the terms would be much more dense, cf. A308560.

Links

Table of n, a(n) for n=1..54.

Example

12 is divisible by 1 + 2 = 3, but 11 is not divisible by 1 + 1.
1512 is divisible by 1 + 5 = 6, 1 + 1 = 2, 1 + 2 = 3 and 5 + 2 = 7.
For single-digit numbers there is no such sum and therefore no divisibility condition, so they are in the sequence.

Prog

(PARI) is(n, d=digits(n))={vecmin(d)&&n>9&&0==n%lcm(concat(vector(-1+n=#d, i, t=d[1+n-i]; vector(n-i, j, t+d[j]))))}

Crossrefs

Cf. A308560, A308534.

Sequence in context: A217973 A097518 A097569 * A095160 A356350 A288528

Adjacent sequences: A308558 A308559 A308560 * A308562 A308563 A308564

Keyword

nonn,base

Author

M. F. Hasler, Jun 07 2019

Status

approved