OFFSET

1,2

COMMENTS

FORMULA

a(n) = SUM[i=1..k] (e_i)*A003132(p_i) where prime decomposition of n = (p_1)^(e_1) * (p_2)^(e_2) * ... * (p_k)^(e_k).

EXAMPLE

a(22) = 6 because 22 = 2 * 11 and the sum of squares of digits of prime factors is 2^2 + 1^2 + 1^2.

a(121) = 4 because 121 = 11^2 = 11 * 11, so 1^2 + 1^2 + 1^2 + 1^2 = 4.

MATHEMATICA

Join[{0}, Table[Total[Flatten[IntegerDigits/@(Flatten[Table[#[[1]], #[[2]]]&/@ FactorInteger[ n]])]^2], {n, 2, 60}]] (* Harvey P. Dale, Nov 17 2022 *)

CROSSREFS

KEYWORD

base,easy,nonn

AUTHOR

Jonathan Vos Post, May 07 2006

EXTENSIONS

a(0) removed by Andrey Zabolotskiy, Jun 08 2024

STATUS

approved