OFFSET
1,1
REFERENCES
C. A. Pickover, "Keys to Infinity", New York: Wiley, p. 7, 1995.
LINKS
Eric Weisstein's World of Mathematics, Super-d Number.
MATHEMATICA
Select[Range[80*10^5], PalindromeQ[#]&&SequenceCount[IntegerDigits[4#^4], {4, 4, 4, 4}]>0&] (* Harvey P. Dale, Jan 18 2023 *)
CROSSREFS
KEYWORD
nonn,base,changed
AUTHOR
Patrick De Geest, May 15 1998
STATUS
approved