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A257950
Numbers n which are both happy (A007770) and bihappy (A257795) numbers.
1
1, 10, 100, 103, 301, 367, 608, 806, 1000, 1030, 3010, 3056, 5630, 6080, 6703, 6791, 8060, 9167, 10000, 10003, 10275, 10300, 11241, 12770, 12939, 13929, 14112, 17027, 17502, 20175, 21921, 22119, 27501, 30001, 30067, 30100, 30616, 31606, 36700
OFFSET
1,2
COMMENTS
This sequence is infinite, because it contains infinite subsequences (powers of 10, for example).
LINKS
FORMULA
All 10^k are members of this sequence.
If n is a member each permutation of a set of pairs of digits gives another members (example 367 and 6703).
Placing two zeros between the sets of two digits gives another member.
EXAMPLE
367 is member of this sequence because 367 = 3^2+6^2+7^2= 94 => 9^2+4^2 = 97 => 9^2+7^2 = 130 => 1^2+3^2+0^2 = 10 => 1^2+0^2 = 1, so after five iterations 367 reaches 1. And 3^2+67^2 = 4498 => 44^2+98^2= 11540 => 1^2+15^2+40^2 = 1826 => 18^2+26^2 = 1000 => 10^2+0^2 = 100 =>1^2+0^2 = 1, so in 6 iterations 367 reaches 1.
CROSSREFS
Sequence in context: A342135 A169665 A257795 * A052009 A355592 A357300
KEYWORD
nonn,base
AUTHOR
Pieter Post, May 14 2015
STATUS
approved