A077377 Squarefree numbers whose external digits form a squarefree number.

1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 26, 29, 30, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 46, 47, 51, 53, 55, 57, 58, 59, 61, 62, 65, 66, 67, 69, 70, 71, 73, 74, 77, 78, 79, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 103, 105, 107, 109, 110, 111, 113

Offset

1,2

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Prog

(PARI) list(lim)=my(v=List(), n, t); for(d=0, logint(lim\=1, 10), t=10^d; forsquarefree(k=t, min(10*t-1, lim), if(issquarefree(k[1]\t*10 + k[1]%10), listput(v, k[1])))); Vec(v) \\ Charles R Greathouse IV, Feb 14 2018

Crossrefs

Cf. A077376, A077378, A077379, A077380.

Sequence in context: A076144 A005117 A144338 * A076786 A298540 A326535

Adjacent sequences: A077374 A077375 A077376 * A077378 A077379 A077380

Keyword

base,easy,nonn

Author

Amarnath Murthy, Nov 06 2002

Extensions

a(1) inserted by Charles R Greathouse IV, Feb 14 2018

Status

approved