OFFSET
1,2
COMMENTS
Each row begins with 1 and has length A046019(n).
LINKS
T. D. Noe, Rows n = 1..1000 of triangle, flattened
V. Oxman and M. Stupel, A number whose square root is the sum of its digits, The Mathematical Gazette 108 (573) (2024), 513-514.
EXAMPLE
1, 2, 3, 4, 5, 6, 7, 8, 9;
1, 9;
1, 8, 17, 18, 26, 27; (A046459, with 0)
1, 7, 22, 25, 28, 36; (A055575 " )
1, 28, 35, 36, 46; (A055576 " )
1, 18, 45, 54, 64; (A055577 " )
1, 18, 27, 31, 34, 43, 53, 58, 68; (A226971 " )
1, 46, 54, 63;
1, 54, 71, 81,
1, 82, 85, 94, 97, 106, 117,
1, 98, 107, 108, etc.
PROG
(Python)
def ok(k, r): return sum(map(int, str(k**r))) == k
def agen(rows, startrow=1, withzero=0):
for r in range(startrow, rows + startrow):
d, lim = 1, 1
while lim < r*9*d: d, lim = d+1, lim*10
yield from [k for k in range(1-withzero, lim+1) if ok(k, r)]
print([an for an in agen(13)]) # Michael S. Branicky, May 23 2021
CROSSREFS
KEYWORD
base,tabf,nonn
AUTHOR
T. D. Noe, Nov 26 2008
STATUS
approved