OFFSET
2,1
LINKS
Scott R. Shannon, Table of n, a(n) for n = 2..404
FORMULA
a(n) = 2*n + 2 if n = 2^k - 1 with k >= 2, otherwise a(n) = n^2 if n is prime.
EXAMPLE
a(4) = 30 as 30 = 2 * 3 * 5 = 132_4 = 2_4 * 3_4 * 11_4, and both 132_4 and its primes factors contain the same distinct digits 1, 2, and 3.
a(10) = 132 as 132 = 2 * 3 * 11, and both 132 and its primes factors contain the same distinct digits 1, 2, and 3. See also A035141.
a(14) = 465 as 465 = 3 * 5 * 31 = 253_14 = 3_14 * 5_14 * 23_14, and both 253_14 and its primes factors contain the same distinct digits 2, 3, and 5.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Scott R. Shannon, Apr 29 2024
STATUS
approved