A230356 Nonsquare numbers n such that digit sum of n = digit sum of square part of n.

10, 18, 27, 40, 45, 54, 63, 72, 90, 108, 117, 126, 135, 153, 160, 162, 171, 180, 207, 216, 220, 234, 243, 250, 252, 261, 270, 304, 306, 315, 333, 342, 351, 360, 405, 414, 423, 432, 450, 490, 504, 513, 522, 531, 540, 603, 612, 621, 630, 640, 702, 711, 720, 801, 810, 931

Offset

1,1

Links

Table of n, a(n) for n=1..56.

Example

135 = 2^3*5. Square part of 135 is 9. Digit_sum(135) =9, digit_sum(9) = 9.

Prog

(PARI)
digsum(n)={local (d, p); d=0; p=n; while(p, d+=p%10; p=floor(p/10)); return(d)}
{for (n=2, 10^3, m=n/core(n); if(digsum(n)==digsum(m)&&m<>n, print(n))); }

Crossrefs

Cf. A006753, A230354, A230355, A230357.

Sequence in context: A257512 A125689 A244573 * A100992 A256382 A167607

Adjacent sequences: A230353 A230354 A230355 * A230357 A230358 A230359

Keyword

nonn,base,less

Author

Antonio Roldán, Oct 16 2013

Status

approved