A307831 Number of palindromic decagonal (10-gonal) numbers with exactly n digits.

2, 0, 1, 0, 2, 0, 0, 1, 0, 1, 0, 1, 3, 1, 1, 0, 3, 0, 0, 5

Offset: 1

Author

Robert Price, Apr 30 2019

Keywords

• nonn
• base
• more

Comments

Number of terms in A307827 with exactly n digits.

Examples

			There are only two 5 digit decagonal numbers that are palindromic, 27972 and 76867. Thus, a(5)=2.
		

Links

• G. J. Simmons, Palindromic powers, J. Rec. Math., 3 (No. 2, 1970), 93-98. [Annotated scanned copy] See page 95.

Crossrefs

Cf. A001107, A307827, A307829, A307830, A307807.

Programs

Mathematica

A307827 = {0, 1, 232, 27972, 76867, 25555552, 7154664517, 158229922851, 2028787878202, 2040061600402, 2733623263372, 52667666676625, 675972505279576, 28519896169891582, 73542836563824537, 74529570707592547, 25552469511596425552, 27835145788754153872, 62740719088091704726, 67047523077032574076, 77979812588521897977, 107838025535520838701};
Table[Length[ Select[A307827, IntegerLength[#] == n || (n == 1 && # == 0) &]], {n, 20}]