A316487 Squares whose arithmetic mean of digits is 7 (i.e., the sum of digits is 7 times the number of digits).

2778889, 4695889, 5678689, 5697769, 5938969, 6568969, 6589489, 6848689, 6895876, 7974976, 7997584, 8779369, 9878449, 9966649, 299739969, 377796969, 396686889, 458687889, 467986689, 487658889, 488984769, 496977849, 538889796, 557998884, 559984896, 569967876

Offset: 1

Author

Jon E. Schoenfield, Jul 04 2018

Keywords

• nonn
• base

Comments

Each term's number of digits is in A056991 (Numbers with digital root 1, 4, 7, or 9). For every term k in A056991, this sequence contains at least one k-digit term, with the exception of k=1 and k=4. (See A316480.)

Examples

			17313^2 = 299739969, a 9-digit number whose digit sum is 2+9+9+7+3+9+9+6+9 = 63 = 7*9, so 299739969 is a term.
43474^2 = 1889988676, a 10-digit number whose digit sum is 1+8+8+9+9+8+8+6+7+6 = 70 = 7*10, so 1889988676 is a term.
		

Links

• Jon E. Schoenfield, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A056991, A069711, A316480.

Intersection of A000290 and A061424. - Michel Marcus, Jul 06 2018