A316865 Number of times 4 appears in decimal expansion of n.

0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1

Offset

0,45

Links

Table of n, a(n) for n=0..104.

Example

a(0) = 0 since the decimal representation of 0 does not contain the digit 4.
a(4) = 1 since 4 appears once in the decimal expansion of 4.

Mathematica

Array[ DigitCount[#, 10, 4] &, 105, 0]

Prog

(PARI) a(n) = #select(x->x==4, digits(n)); \\ Michel Marcus, Jul 20 2018

Crossrefs

Cf. A043505, A043506, A043507, A043508.

Cf. A055641, A268643, A316863, A316864, A316866, A316867, A316868, A316869, A102683.

Sequence in context: A218245 A352516 A086075 * A325616 A056978 A321761

Adjacent sequences: A316862 A316863 A316864 * A316866 A316867 A316868

Keyword

base,easy,nonn

Author

Robert G. Wilson v, Jul 15 2018

Status

approved