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

1,1

Comments

This is really four sequences, not one! A050498 is a better version. - N. J. A. Sloane, Jan 01 2005

References

D. Wells, Curious and interesting numbers, Penguin Books, p. 112 (but beware errors).

Links

Table of n, a(n) for n=1..34.

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

Crossrefs

Sequence in context: A181466 A243541 A138691 * A065147 A214226 A043187

Adjacent sequences: A039667 A039668 A039669 * A039671 A039672 A039673

Keyword

nonn

Author

Felice Russo

Extensions

Corrected by Jud McCranie, Dec 26 1999

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 29 2004

Status

approved