A039670 Sets of 4 numbers in arithmetic progression with common difference 6 and whose phi values are equal.
72, 78, 84, 90, 216, 222, 228, 234, 76326, 76332, 76338, 76344, 101526, 101532, 101538, 101544, 116646, 116652, 116658, 116664, 146886, 146892, 146898, 146904, 298086, 298092, 298098, 298104, 369366, 369372, 369378, 369384, 624966, 624972
Offset: 1
Keywords
References
- D. Wells, Curious and interesting numbers, Penguin Books, p. 112 (but beware errors).
Programs
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Maple
with(numtheory):for n from 1 to 1000000 do if(phi(n)=phi(n+6) and phi(n+6)=phi(n+12) and phi(n+12)=phi(n+18)) then printf("%d, %d, %d, %d, ",n,n+6,n+12,n+18) fi od: # C. Ronaldo
Extensions
Corrected by Jud McCranie, Dec 26 1999
More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 29 2004
Comments